Posts Tagged ‘ Electronics ’

The Oscilloscope

The Oscilloscope:
If you do decide that you are going to research new equipment, design and possibly invent new devices, then an oscilloscope is useful.   Let me stress again that this is not an essential item of equipment and most certainly is not needed until you are quite familiar with constructing prototypes.   It is quite easy to misread the settings of an oscilloscope and the methods of operation take some getting used to.   The low-cost book “How to Use Oscilloscopes and Other Test Equipment” by R.A. Penfold, ISBN 0 85934 212 3 might well be helpful when starting to use a ‘scope.

It is possible to get an oscilloscope at reasonable cost by buying second-hand through eBay.   The best scopes are ‘dual trace’ which means that they can display the input waveform and the output waveform on screen at the same time.   This is a very useful feature, but because it is, the scope which have that facility sell at higher prices.   The higher the frequency which the scope can handle, the more useful it is, but again, the higher the selling price.   Not all scopes are supplied with (the essential) ‘test probes’, so it might be necessary to buy them separately if the seller wants to keep his.   Getting the manual for the scope is also a decided plus.   A low cost scope might look like this:

Magnetic Measurement.   People who experiment with permanent magnets, can make use of an instrument which displays the strength of a magnetic field. Professionally made devices to do this tend to be well outside the purchasing power of the average experimenter who will already have spent money on materials for his prototypes. Here is a design for a simple and cheap circuit, powered by four AA dry cell batteries, and utilising a Hall-effect semiconductor as the sensor:

This design uses an OP77GP operational amplifier chip to boost the output signal from the A1302 chip which is a Hall-effect device. The gain of the DC-connected operational amplifier is set by the ratio of the 1K and 1M fixed resistors shown shaded in the circuit diagram, giving a gain of 1,000.

The circuit operation is simple. The six-volt battery charges the 10 microfarad capacitor which helps iron out any supply line fluctuations caused by varying current draw by the circuit. The 10K variable resistor is used to set the output meter display to zero when the Hall-effect device is not near any magnet. The 1K variable resistor is there to make fine tuning adjustments easier.

When the A1302 chip encounters a magnetic field, the voltage on it’s output pin 3 changes. This change is magnified a thousand times by the OP77GP amplifier. It’s output on pin 6 is connected to one side of the display meter and the other side of the meter is connected to point “A”. The voltage on point “A” is about half the battery voltage. It would be exactly half the voltage if the two 4.7K resistors were exactly the same value. This is rather unlikely as there is a manufacturing tolerance, typically around 10% of the nominal value of the resistor. The exact value of the voltage on point “A” is matched by the OP77GP tuning and so the meter reads zero until a magnetic field is encountered. When that happens, the meter deflection is directly proportional to the strength of the magnetic field.

Electronics Tutorial


Test Equipment

Test Equipment
When developing new circuitry, it may be convenient to try different values of resistor in some position in the circuit (the resistor value may be dependent on the gain of a transistor or the actual resistance of an ORP12, or some such other situation).   For this, it is very convenient to have a resistor-substitution box which allows you to select any standard resistor at the turn of a switch.

These are not readily available on the market.   In years gone by, it was possible to buy custom wafer switches, where the number of wafers could be built up to whatever switch size was required, but these do not seem to be available any more.   A slightly less convenient method of construction is to use four of these, selected by a second wafer switch:

In the above diagram, all of the resistors in one range (100 ohms to 820 ohms, 1K to 8K2, 10K to 82K or 100K to 820K) are wired to a single 12-way switch.   The output wires then have any of these standard resistors across them, depending on the setting of the switch.   A second switch can then be used to select several of these groups, while still using the same output wires.   When boxed, it might look like this:

It can also be useful to have a versatile signal generator.   You can easily construct your own with variable frequency, variable mark/space ratio and optional variable gating.   If you do, you might as well make it with a low output impedance so that it can drive devices under test directly rather than having to provide additional buffering.   It might look like this:

The really essential item of equipment is a multimeter.   These come in many shapes, sizes and varieties and the cost varies enormously.   The reliability also varies a great deal.   The most reliable and the cheapest is the analogue type which does not use a battery (other than for the occasional measurement of resistance).   Although these types are looked down upon nowadays, they are 100% reliable:

The meter shown above is rated at 2,000 ohms per volt, so connecting it to a circuit to make a measurement on the 10V range is the same as connecting a 20K resistor to the circuit.   The big brother of this style of equipment is about five times larger and has 30,000 ohms per volt performance, so connecting it on a 10V range is the same as connecting a 300K resistor to the circuit being measured.   This one is battery driven, so if you get one of these, may I suggest that you check its accuracy on a regular basis:

The really excellent non-battery (ex-professional) Avo meter multimeters are still available through eBay at affordable prices.   These have 30,000 ohms per volt performance and are robust and accurate, having been built to very high standards.

A multimeter uses a 1.5V battery to measure resistance.   Ohm’s Law is used as the working principle and the operation is:

The meter shown in the diagram has a small resistance of its own.   This has a small variable resistor added to it.   This variable resistor will have a small knob mounted on the face of the multimeter, or it will be a thumbwheel knob projecting slightly from the right hand side of the multimeter case.   The 1.5V battery will be positioned inside the multimeter case as is the 1K resistor.   To use the resistance ranges, the multimeter probes are touched firmly together to form a short-circuit and the variable resistor adjusted so that the meter points to zero.

For the purpose of this discussion, let us assume that the internal resistance of the meter, when correctly adjusted, is exactly 1K.   If the resistor under test is exactly 1K in value, then the current through the meter will be halved and the meter will show a needle deflection half way across the scale.   If the resistor under test is 2K, then the current will be one third and the scale marking will be at the 1/3 position from the left.   If the resistor is 4K, then there will be one fifth (1K+4K=5K) of the full-scale current and the 4K mark will be 20% from the left hand side of the scale.

Two things to notice: firstly, the scale has to read from right to left which can take some getting used to, and secondly, the scale is not linear, with the markings getting closer and closer together and consequently, more difficult to mark and read, the higher the value of the resistor being measured.   The bunching up of the scale markings is why the more expensive multimeters tend to have more than one range.

A mains-operated oscilloscope is an excellent piece of equipment to own but they are expensive when new.   It is possible to pick one up at a reasonable price second-hand via eBay.   An oscilloscope is by no means an essential item of equipment.   One of its most useful features is the ability to measure the frequency, and display the shape of a waveform.   Most waveforms are of known shape so the frequency is the major unknown.   The following meter is not expensive and it displays the frequency of a signal on a digital readout:

So, when you are deciding what multimeter to buy, consider the following points:

    1. How reliable is it?   If you are opting for a battery driven unit, what happens to the accuracy if the battery starts to run down.   Does it display a warning that the battery needs to be replaced?   Mains-operated digital multimeters are brilliant but are a problem if you want to make measurements away from the mains.
    1. What DC voltage ranges does it have?   If you are intending to work mainly with 12V circuits, it is inconvenient for the ranges to be 9V and 30V as successive ranges.   Digital meters do not have this problem but the question then is, how accurate are they going to be in day to day use?
    1. Transistor testing options you can ignore – you are better off making your own dedicated unit to check transistors if you think you will ever need to do this – you probably won’t.
    1. Measuring current can be very useful so see what ranges are offered.
    1. Measuring capacitance is very useful, especially since many capacitors are not well marked to indicate their value.
    1. Measuring the frequency of a waveform could be a significant bonus but the question is; are you every likely to need it?
  1. Measuring resistance is very useful.   Every meter can do it.   There is no need to be over fancy on measurement ranges as you usually only need to know the approximate answer – is it a 1K resistor or a 10K resistor?

Look around and see what is available, how much it costs and what appeals to you.   It might not be a bad idea to buy a really cheap multimeter and use it for a while to see if it has any shortcomings which are a nuisance, and if so, what improvements you personally want from a more expensive meter.

It might be worth getting a fancy bench power supply which allows you to set any voltage you want and which displays the current being drawn by your development circuit:

However, there is no need to spend money on a fancy unit when you can build an excellent unit of your own with voltage stabilisation, adjustable output, metered current, etc. etc.   Personally, if developing a circuit to be used with a battery, I believe you are better off powering the development from a battery, that way the characteristics of the battery are included in any tests which you carry out.

Power Supply:   If you wish, you can construct a very convenient development test bed power supply system.   This has the advantage that you can make it in the most convenient style for your own use.   You can also make the protection ultra-sensitive and build in additional circuitry such as transistor tester and resistor substitution box to produce an integrated test bed.   You could perhaps use a circuit like this:

Here, the power is supplied by a pack of re-chargeable Ni-Cad batteries or possibly, a mains unit with voltage stabilisation.   As in all actual circuits, the next thing in the circuit is always an on/off switch so that the power source can be disconnected immediately should any problem arise.   Next, as always, comes a fuse or circuit breaker, so that should the problem be serious, it can disconnect the circuit faster than you can react.   If you wish, you can build your own super-accurate adjustable circuit breaker to use in this position.

The two transistors and three resistors form an adjustable, stabilised output.   The FET transistor has a high output power handling capacity and a very low input power requirement and so is good for controlling the output voltage.   Resistor ‘VR1’ is padded with the 4K7 resistor solely to reduce the voltage across the variable resistor.   VR1 is adjusted to control the output voltage.   If the current draw is increased and the output voltage is pulled down slightly, then the voltage on the base of the BC109 transistor is reduced.   This starts to turn the transistor off, raising the voltage at point ‘A’, which in turn, raises the output voltage, opposing the variation caused by the load.

The output is monitored, firstly by a large milliammeter to show the current draw and secondly, on the output side of the milliammeter, a voltmeter.   This allows very close monitoring of the power supplied to the prototype, especially if the milliammeter is placed alongside the prototype.   You can build this circuit into a wide flat box which provides a working surface beside the milliammeter.

At point ‘B’ in the above diagram, a method for altering the current range of the milliammeter by placing a ‘shunt’ resistor across it.   When the switch is closed, some current flows through the resistor and some through the milliammeter.   This resistor has a very low value, so you are better off making it yourself.   Let’s say we wish to double the range of the meter.   Solder the switch across the meter and for the resistor use a length of enamelled copper wire wound around a small former.   Put a load on the output so that the meter shows a full-scale deflection.   Close the switch.   If the current displayed is exactly half of what it was, if not, switch off, remove some wire to lower the reading or add some wire to raise the reading and repeat the test until exactly half the current is displayed.   The lower the value of the shunt resistor, the more current flows through it and the less through the meter, which then gives a lower reading.

Please note: it is very important to have a fuse or circuit breaker in the power being delivered to your test circuit.   Any error in building the prototype can cause a major current to be drawn from the supply and this can be dangerous.   Remember, you can’t see the current.   Even if you have a meter on the current being delivered, you may not notice the high reading.   The first sign of trouble may be smoke!   You can easily fry the circuit you are building if you do not have a safety cut-off, so use a fuse or other device which limits the current to twice what you are expecting the circuit to draw.

So, after all that, what equipment do you really need?   You need a small soldering iron and multicore solder, a pair of long-nosed pliers and a multimeter.   One other thing is some tool to cut wires and remove the insulation prior to soldering.   Personal preferences vary.   Some people prefer one of the many custom tools, some people use a knife, I personally use a pair of straight nail scissors.   You pick whatever you are comfortable with.

Not exactly a vast array of essential equipment.   The other items mentioned are not by any means essential so I suggest that you start by keeping things simple and use a minimum of gear.

If you are not familiar with electronics, I suggest that you get a copy of the Maplin catalogue, either from one of their shops or via the Maplin web site.   Go through it carefully as it will show you what components are available, how much they cost and often, how they are used.   The specifications of almost any semiconductor can be found free at AllDataSheet in the form of an Adobe Acrobat document.

Finally, because it is not important, all of the circuitry shown so far has indicated current flowing from the + of a battery to the – terminal.   The discovery of voltage was made by Volta but he had no way of knowing which way the current was flowing, so he guessed.   He had a 50 – 50 chance of getting it right but he was not lucky and got it wrong.   Electrical current is actually a flow of electrons, and these flow from the battery minus to the battery plus.   So, who cares?   Almost nobody, as it has no practical effect on any of the circuitry.

Electronics Tutorial

Prototype Construction

Prototype Construction
The main options for building a prototype circuit are:

1. A breadboard
2. Electrical screw connector strips.
3. Stripboard
4. A printed circuit board.

1. The typical breadboard unit consists of a matrix of clip holes wired in strips, into which component leads can be pushed to make a circuit. In my opinion, they are best avoided as it takes quite some effort to implement any significant circuit using them, some components do not fit well in the sockets which are small enough to take DIL IC packages, and when you do get a circuit working well on the breadboard, there is no guarantee that it will work well when you attempt to move it to a permanent soldered board:

While a plastic board of this type looks as if it should be quick and easy to use, I have never found it to be so ever since the boards were scaled down in size to take the closely-spaced pins of integrated circuits (“chips”). It is generally difficult to lay the components out in the same pattern as the circuit diagram, and if they are not, then it becomes slow to follow the circuit through on the breadboard layout.

2. The local hardware shop has cheap screw connectors which can be very effective. These come in several sizes and the smaller ones are very convenient for constructing transistor circuitry. They look like this:

Circuits can be assembled very easily, using these connectors and an example might be one of the John Bedini battery pulsing circuits which might have a layout like this:

I have built this circuit using this style of construction and it was very successful indeed, being very quick and easy to construct and it proved to be very tough and effective over a long period of use. The plastic strip has a hole between each connector strip and that allows you to bolt the strip to a base board on which you mount other components, in this case, the pulsing coil and the rotor with the magnets attached. Each connection block can take two or three wires. The wires need to have the insulation removed and the wires scraped clean and shiny if they are not already in that state. If more than one multi-strand wire is being put into one side of a connector, then it is usually best to twist the wires together before tightening the clamping screw. If you want, you can give the twisted wires a thin coat of solder, but this has to be done neatly to avoid producing a joint which is too large to fit into the connector. One connector can be cut out of the strip quite easily, using a pair of scissors or a craft knife. Single connectors can join two wires very effectively without the need to solder them.

3. Stripboard, usually called ‘Veroboard’ even if it is not made by Vero, is a quick and satisfactory method, although you have to make very tiny solder joints. Please be aware that the fumes from the burning resin when soldering are most definitely not good for your health and should be avoided by making sure that the ventilation is adequate.

4. A printed circuit board is feasible for a one-off prototype and making one will increase your production skills, so it is also a reasonable option if you have the etching and drilling equipment to hand. Buying all of the necessary equipment if you do not have any, can cost a fair amount, but the skills gained are significant and the finished boards looks very professional.

There are several other methods of construction, and many varieties of construction board and stripboard. Simple stripboard will be used in the following descriptions, although the method does apply to many different styles of construction.

The first step is to produce a layout for the components on the board. When designing the layout provision should be made for drilling holes to allow the completed board to be bolted to its case using bolts and insulating pillars to keep the soldered joints clear of all other surfaces.

The circuit diagram of the circuit to be built is the starting point.   You might wish to draw a light grid of lines to represent the matrix of holes in the strip board.   This helps to visualise the run of the copper strips and the sketch can be made to show the exact number of holes available on the piece of strip board to be used.   The strip board looks like this:

So you might wish to produce a layout sketch re-usable drawing like this:

where the horizontal strips are numbered and the vertical lines of holes are also numbered.   In this sketch, where the lines cross, represents a hole in the board.   The sketch of a possible physical layout can then be prepared and it might look like this when seen from the top although the copper strips on the underside of the board are shown in the sketch:

It is very important when producing a sketch like this, that the copper strips making up the circuit are not accidentally used to connect components further along the board, without breaking the copper strip between the two sections of the board.   It helps to mark a copy of the circuit diagram when you are sketching a possible physical layout on the strip board.   It might be done like this:

Here, the components just below the diode are ringed to show that they have been marked on the layout sketch and, if necessary, the copper strip broken to isolate the components.   A component worth mentioning in passing, is the capacitor marked with red in the circuit diagram.   This is a decoupling capacitor, fed from the 12V battery via a resistor and a diode (a diode is not normally used in this part of the circuit).

The decoupling is to provide the 555 chip and drivers with a supply which is reasonably isolated from the heavy current-draw circuit not shown in this small section of the circuit diagram.   The pulsating heavy current draw of the rest of the circuit is capable of pulling the battery voltage down slightly many times per second.   This creates a voltage ripple on the positive supply line from the battery and to smother the ripple, the resistor and diode are used to feed a large reservoir capacitor which smoothes out the ripple.

The circuit itself is not beyond criticism.   Transistor ‘TR2’ and its associated components are redundant since pin 3 of the 555 chip already supplies the required signal (and with higher drive capacity) so the second output line should be taken directly from pin 3 of the 555 chip.   This snippet of circuit is only shown here as an example of marking up a circuit diagram when making a components layout sketch.

As the layout sketch is produced, the circuit diagram should be marked off with a highlighting pen to make sure that every part of the circuit diagram has been successfully copied to the sketch.   In the example below, not all of the highlighted strip is shown, since it runs off the small section of the board being shown here:

Many electronic components can be damaged by the high temperatures they are subjected to when being soldered in place.   I personally prefer to use a pair of long-nosed pliers to grip the component leads on the upper side of the board while making the solder joint on the underside of the board.   The heat running up the component lead then gets diverted into the large volume of metal in the pair of pliers and the component is protected from excessive heat.   On the same principle, I always use a DIL socket when soldering a circuit board, that way, the heat has dissipated fully before the IC is plugged into the socket.   It also has the advantage that the IC can be replaced without any difficulty should it become damaged.

If you are using CMOS integrated circuits in any construction, you need to avoid static electricity.   Very high levels of voltage build up on your clothes through brushing against objects.   This voltage is in the thousands of volts range.   It can supply so little current that it does not bother you and you probably do not notice it.   CMOS devices operate on such low amounts of current that they can very easily be damaged by your static electricity.   Computer hardware professionals wear an earthing lead strapped to their wrists when handling CMOS circuitry.   There is no need for you to go that far.   CMOS devices are supplied with their leads embedded in a conducting material.   Leave them in the material until you are ready to plug them into the circuit and then only hold the plastic body of the case and do not touch any of the pins.   Once in place in the circuit, the circuit components will prevent the build up of static charges on the chip.

Soldering is an easily-acquired skill.   Multi-cored solder is used for electronic circuit soldering.   This solder wire has flux resin contained within it and when melted on a metal surface, the flux removes the oxide layer on the metal, allowing a proper electrical joint to be made.   Consequently, it is important that the solder is placed on the joint area and the soldering iron placed on it when it is already in position.   If this is done, the flux can clean the joint area and the joint will be good.   If the solder is placed on the soldering iron and then the iron moved to the joint, the flux will have burnt away before the joint area is reached and the resulting joint will not be good.

A good solder joint will have a smooth shiny surface and pulling any wire going into the joint will have no effect as the wire is now solidly incorporated into the joint.   Making a good solder joint takes about half a second and certainly not more than one second.   You want to remove the soldering iron from the joint before an excessive amount of heat is run into the joint.   It is recommended that a good mechanical joint be made before soldering when connecting a wire to some form of terminal (this is often not possible).

The technique which I use is to stand the solder up on the workbench and bend the end so that it is sloping downwards towards me.   The lead of the component to be soldered is placed in the hole in the strip board and gripped just above the board with long-nosed pliers.   The board is turned upside down and the left thumb used to clamp the board against the pliers.   The board and pliers are then moved underneath the solder and positioned so that the solder lies on the copper strip, touching the component lead.   The right hand is now used to place the soldering iron briefly on the solder.   This melts the solder on the joint, allowing the flux to clean the area and producing a good joint.   After the joint is made, the board is still held with the pliers until the joint has cooled down.

Electronics Tutorial

Choosing Your Components

Choosing components which are not specified.
Some people find it difficult to select a suitable component where the exact component is not specified or where an alternative has to be selected, so perhaps a few general pointers might be helpful. The reason why component values are omitted may well be because a very wide range of alternative values can be used and if one particular is specified, the newcomers to electronics feel that they have to use that one value or the circuit will not work, (which is almost never the case). For example, I have been asked if a capacitor rated at 25V could be used instead of the same value capacitor rated at 16V shown in the circuit, to which the answer is ‘yes, most definitely’. The lower voltage rating is adequate and the component cheaper to buy, but if one of a higher voltage rating is available, then it can be used.

With capacitors, you need to consider the physical size and wire connections, the capacitance, the voltage rating, and the leakage. The cost and size of a capacitor is directly related to it’s voltage rating, and once the voltage rating exceeds that normally used, the price shoots up rapidly as the sales volume reduces rapidly, which in turn, discourages further sales. This sometimes causes circuit builders to connect chains of cheaper capacitors together to make a smaller-capacity high-voltage capacitor. In the case of Tesla Coil builders, they then may connect several of these chains in parallel to boost the capacitance.

If the voltage rating is exceeded (usually by a very large amount), the capacitor will be damaged and become either a short-circuit, or more likely, an open circuit. Either way, it will never work as a capacitor again. In a household circuit, where the capacitor is being used as part of the power supply to the circuit, the voltage rating does not need to be much higher than the supply voltage, with say, 16V being used for a 12V circuit. You could use a capacitor rated at 25V, 40V, 63V, 100V or 400V and it would work perfectly well, but it will be much larger and have cost much more. But, if you have one sitting around and not being used, there is no reason why you should not use it rather than paying to buy another one.

If the capacitor is being used in a timing circuit where a high-value resistor is feeding current to it, then the leakage current of the capacitor becomes very important. Electrolytic capacitors are seldom suitable for such an application as they have a small, unpredictable leakage current which will vary with the age of the capacitor. For accurate timing with a capacitor, ceramic, polypropylene, mylar or tantalum should be used.

The voltage rating for an electrolytic capacitor is for DC, so if you use it for limiting current in an AC power supply, that is, where the current flows through the capacitor rather than the capacitor being placed across the supply and is acting to combat ripple, then great care is needed. The capacitor will heat up due to the power flowing through it, and it is possible for an electrolytic capacitor used in that way to rupture or ‘explode’ due to the electrolyte boiling. Instead, you need to use the very much more expensive oil-filled can capacitors (as shown near the end of chapter 10). That style of usage is unusual for home constructors.

With bi-polar transistors, you need to use commonsense. Suppose a 555 timer chip is required to power a transistor which controls a relay:

For the moment, we will ignore the fact that the 555 could drive the relay directly without the need for a transistor. let’s say that the relay draws a current of 30 mA when connected to a 12V supply. Therefore, the transistor needs to be able to handle a current of 30 mA. Any small switching transistor such as the BC109 or 2N2222 can easily handle that current. The transistor also needs to be able to handle 12 volts. If in doubt, look up the characteristics of your choice of transistor at alldatasheet by entering the transistor name ‘BC109’ or whatever in the entry box at the top of the screen and clicking on the button to the right of it. Eventually, it will let you download a pdf document specifying the transistor, and that will show you the voltages which the transistor can handle. Both of the above transistors can handle far more than 12V.

The next question is, ‘can the transistor switch fast enough to work in this circuit?’ and the data sheet will show that they can switch on and off a million times per second. As the relay can only switch on and off a few times per second, the transistor can easily operate fast enough to handle the switching.

Next, we need to know what size of resistor would be suitable. The data sheet will also show the DC current gain of the transistor. This is usually marked as “hfe” and for these transistors is likely to be a minimum of, say, 200. This means that the current flowing into the base of the transistor needs to be one two-hundredth of the relay’s 30 mA which is 0.15 mA. The resistor will have about +11 volts at pin 3 of the 555 timer and around +0.7 volts at the base of the transistor when it is switched fully on. That means that the resistor will have about 10.3 volts across it when the relay is switched on:

So, what size of resistor will have 0.15 mA flowing through it when there is a 10.3-volt drop across it? We know that a 1K resistor passes 1mA per volt and so would pass 10.3 mA with 10.3 volts across it. That is far more than we need. A 10K resistor would pass 1.03 mA which is still far too much but certainly could be used. As it is a resistor, we can use Ohm’s Law: R = V / A (Ohms equals Volts over Amps), or R = 10.3 / 0.00015 which is 68K. So, any resistor between 68K and perhaps 15K should work well.

The diode is there to protect the transistor from excessive voltage caused by the coil of the relay. When a coil is switched off suddenly, it generates a reverse voltage which can be hundreds of volts, pulling the collector of the transistor far above the +12V power supply line. When that starts to happen, it effectively reverses the diode direction, allowing it to conduct and short-circuit that big voltage spike:

Due to the short-circuiting, the voltage can’t get any higher and the current through the diode is not large, so most diodes such as the popular and cheap 1N4001 or 1N4007 types can be used.

When a transistor is connected like that and switched on, it is effectively a short-circuit between it’s collector and emitter, and that places the full 12 volts across the relay, powering it very solidly. This connection method is called a “common-emitter” circuit because all of the transistors used have their emitters all wired in common to the 0V line. An alternative arrangement is the “emitter-follower” circuit:

With this circuit arrangement, the emitter of the transistor “follows” the voltage on pin 3 of the 555 timer. It is always a constant voltage below it, typically about 0.7 volts. The output of the 555 timer has a maximum of about 0.7V below the supply voltage, and so it’s maximum value is about 11.3V in this circuit. The transistor drops that by a further 0.7V, which means that the relay only gets about 10.6V across it instead of the full 12V of the supply, which means that it should be a 10-volt relay rather than a 12-volts relay.

Those are the easy cases because the 555 timer can supply at least 200 mA through it’s output pin, while keeping the output voltage steady. That is not the case with simple transistor circuits. Take a situation like this:

For audio work – microphone pre-amplifiers and the like – the rule of thumb is that the current flowing through the first transistor should be at least ten times the current required by the base of the second transistor in order not to drag down and distort the audio waveform.

Relay switching is not so critical but the same general principle applies and attention needs to paid to the collector resistor of the preceeding transistor. For example, if the current flowing through the preceeding transistor is small, say, 0.5 mA and the output transistor needs 1.5 mA flowing into it’s base, then there can be a problem. In this circuit, for example:

Here, the voltage at point “A” goes high because the first transistor switches off and so becomes the same as a resistor of 1Meg or more. Normally, that resistance is so much greater than the 27K of it’s resistor, that the voltage at point “A” would be nearly +12V, but if you were to connect the resistor “R” of just 1K in value, then the situation is changed completely. the base of “Tr” can’t rise above 0.7V. The first transistor can be ignore due to its very high resistance. That leaves a voltage-divider pair of resistors, the 27K and the 1K, with 11.3 volts across them, stopping the voltage at point “A” from rising above 1.13V instead of the original 12V and transistor “Tr” will only get 0.43 mA instead of the 1.5 mA which was wanted. The transistor “Tr” has effectively a 28K resistor feeding it current from the +12V rail.

One solution would be to raise the current through the first transistor by using a resistor a good deal smaller than the present 27K. Another option is to lower the input current requirement of transistor “Tr” by making it a Darlington pair or by using a transistor with a much higher gain.

Electronics Tutorial

The 4022 Chip

The ‘4022’ Chip
One very useful CMOS integrated circuit is the ‘4022’ chip which is a 16-pin ‘divide by 8’ chip with built-in decoding.   The connections are:

If pin 14 is provided with the output from some variety of astable multivibrator, on the first pulse, this chip sets the “0” output on pin 2 to High while the other outputs are Low.   On the next pulse, the “0” output goes Low and the “1” output on pin 1 goes High.   On the next pulse, output “1” goes Low and the “2” output on pin 3, goes High.   And so on until on the eighth pulse, output “7” on pin 10 goes Low and output “0” goes high again.

The chip can also divide by lower numbers:

For ‘Divide by 7’ operation, connect pin 10 to pin 15 (this resets the output to ‘0’)
For ‘Divide by 6’ operation, connect pin 5 to pin 15
For ‘Divide by 5’ operation, connect pin 4 to pin 15
For ‘Divide by 4’ operation, connect pin 11 to pin 15
For ‘Divide by 3’ operation, connect pin 7 to pin 15
For ‘Divide by 2’ operation, connect pin 3 to pin 15

If you want a ‘Divide by 1’ circuit, I suggest you cut down on the amount of alcohol you drink.

Here is an illustration of a ‘Divide by 4’ setup:

There are a number of things to notice in the above diagram.   Firstly, the practical arrangements for circuitry have not been stressed before.   If the circuitry has a pulsing circuit drawing heavy current, as shown by the thick red arrows, then it should be physically connected to the battery and any low-current circuitry should be further away from the battery.   The supply from the battery should have a fuse or circuit breaker and a switch in the line before anything else is connected, so that if any component develops a fault and goes short-circuit, the fuse will blow and prevent any significant problems.

Secondly, it is a good idea to provide the other circuitry with a smoothed power supply as shown by the blue components in the diagram.   This minimises the effect if the battery voltage gets pulled down by the pulsing of the high-current circuitry.   The diode (silicon, 1 Amp, 50 V) stops the heavy current circuit drawing current from the large smoothing capacitor.   The 100 ohm resistor limits the current into the large capacitor on switch-on and provides a little more smoothing.   This circuitry is called “de-coupling” as it de-couples the low current circuitry from the high current circuitry.

Thirdly, notice capacitor “C1” which is wired physically as close to the power supply pins of the integrated circuit as is possible.   If a spike is superimposed on the battery supply, then this capacitor soaks it up and prevents it damaging or triggering the integrated circuit.   A spike could be caused by a very strong magnetic pulse nearby as that can induce an extra voltage in the battery wires.

The lower part of the diagram shows the output voltages produced as the clock pulses reach pin 14 of the chip.   The positive-going part of the clock signal triggers the change in state of the outputs.   If necessary, a positive-going pulse on the reset pin, pin 15, causes output “0” to go high and the other outputs to go low.

Now, to take this output sequencing a little further. For example, the Charles Flynn magnet motor shown in Chapter 1 needs coils to be powered up, one after the other and only one should be on at any one time. This calls for a circuit which has a large number of outputs. The CD4022BC chip gives up to eight outputs one after the other. The CD4017B chip gives up to ten outputs one after the other but there is no need to be limited by these numbers as more than one chip can be used. If you find this section difficult to understand, then just skip past to the next section as it is not important for you to understand these larger circuits.

The pin connections for the divide-by-ten CD4017B chip is shown here:

While this shows outputs 1 to 10, the manufacturers and some people who draw circuits, prefer to label the outputs as “0 to 9” which correspond to digital displays. In our style of operation, it is easier to think of the ten outputs as being from 1 to 10.

You will notice that there are two pin labels which we have not come across before, namely, the “Carry-out” pin and the “Clock Enable” pin. These allow us to use several of these chips in a row to give a much larger “divide-by” number. The “Clock Enable” pin can be used to block the clock input. The operation is like this:

In this example, the sequence is started by the Reset pin being given a high voltage as shown by the green shading. This pushes the output pin 1 to a high voltage and all of the other outputs to a low voltage and holds those voltages as long as the reset voltage is high.

When the Reset voltage drops, the next rising edge of the clock pulse (marked “1” in the diagram) causes the output 1 to go low and output 2 to go high. Each of the successive clock pulses “2” to “9” moves the high voltage steadily along the outputs until output pin 10 is high.

The next clock pulse rising edge (marked “10” in the diagram) starts the sequence again with output 10 going low and output 1 going high again. If nothing changes, then that sequence of output voltage changes will continue indefinitely.

However, in the diagram above, the Clock Enable pin voltage is driven high on clock pulse “11”. Output 2 has just gone high and would have gone low when the rising edge of clock pulse “12” occured, but in this case, the Clock Enable feature blocks the clock pulse and prevents it reaching the rest of the circuitry. This causes the output 2 voltage to stay high as long as the Clock Enable remains high. In this example, the Clock Enable voltage stays high for just one clock pulse, causing the output 2 voltage to be high for twice it’s usual length, and then the sequence continues as before.

Here is one way to get a large “divide-by” number. This example is divide-by-25 because there is only one ‘intermediate stage’ but there can be any number and each additional one adds another eight outputs to the total:

At startup, output 10 of the first stage (which is physical pin 11 of the chip) is at a low voltage. This holds the Clock Enable (pin 13) low, allowing the clock pulses to enter the first stage. Because the output 10 voltage is low, one input to the first AND gate is held low, preventing it from letting the clock pulse flow through it, i.e. the “gate” is closed to through traffic.

The first stage chip then operates as normal, producing outputs 1 to 9 in order as you would expect. The next clock pulse stes the first stage output 10 high, allowing the clock pulses through the first AND gate and holding the Clock Enable (pin 13) high, which in turn locks the output 10 high, dropping the first stage chip out of the operation.

As the output 1 of the first stage is connected to the Reset (pin 15) of the second chip, it will have been cleared and it’s output 1 set high, which in turn Resets the third chip and closes the second AND gate. So, when the first pulse gets through to the second chip, it pushes it from state 1 to state 2 where the output 2 goes high. For that reason, output 1 of the second chip is not one of the outputs which can be used by whatever following circuitry you choose to connect to this system. Consequently, only eight of the ten outputs of the second chip are available as counter outputs. That is, outputs 1 and 10 are taken up in passing the switching sequence between the various chips in the chain.

The same applies to all following chips in the chain, each extra chip adding up to eight extra sequential outputs. On the final stage chip, if you connect the red Reset wire (which goes back to fire up the first chip again) to output 9 instead of output 10 of the final chip, then you get a divide-by-24 result.

If the Reset is taken from output 8 of the final chip, then you get a divide-by-23 result, and so on. Using this method, you can have a divide-by circuit for any number you want. These chips are very popular and so their cost is low, amking the entire circuit cheap to make. The pin connections for the AND gates is shown here:

The PIC Revolution. Over the years, there have been advances in the way that circuitry can be put together, prototypes built and tested. Initially, “valves” or “vacuum tubes” were used and circuits required a good deal of electrical power in order to operate. Mechanical vibrators or “reeds” were used to generate the switching needed to convert DC into AC. Then the transistor became widely available and the transistor replaced the mechanical vibrator reed, the circuit being called an “astable multivibrator” and comprising of two transistors wired back to back (as described in chapter 12). Then came the digital integrated circuit with it’s “NOR gates” which could also be wired back to back to make a multivibrator. This was done so often that a special integrated circuit called the “555 chip” was designed to do the job all on its own. That chip has been a tremendous success and is now found in all sorts of different circuits, being very easy to use, very robust and very cheap. Surprisingly, the dominant position of the “555” chip is being challenged by a completely different type of chip, one which is essentially, a computer on a single chip, and which is called a “PIC controller”.

This new type of chip is not expensive, is easy to use, and can be changed to perform a different task in just a few seconds. It can perform timing tasks. It can act as a multivibrator. It can act as a “Divide-by-N” chip. It is a very impressive chip which is very useful. The reason that I mention it here is because it is at the heart of the fastest working Tesla Switch research forum around (the “energetic forum” group). The chip is something you need to know about as it will certainly take over more and more circuit applications in the coming years.

There is a whole family of these processor chips, but I will select just one for this description, and that will be the one being used by the “energetic forum” members, and I have to thank Jeff Wilson for his help in describing this circuitry, the programming and the methods which he uses.

First, however, some information on this new design of chip and the methods used with it. The one used by Jeff is called the “PICAXE-18X” and it looks like the chip shown here. From which you can see, it looks just like any other chip, although with eighteen pins. The powerful performance comes from the way that it operates. You are probably familiar with the “555” chip and understand that it operates by changing the voltage on just one of it’s pins (pin 3) the output pin, from a low voltage to a high voltage. The PIC chip can do that as well, but even better still, it has more than one output pin and it can alter the voltage on any of those pins to either a high or a low voltage and it can do that in any order and with any timing that you choose. This makes it a very versatile chip indeed and one which is very well suited to be the central controller for a Tesla Switch test environment.

The chip is used by wiring it into a circuit in the same sort of way that a 555 chip would be used, except that the PIC has it’s own internal timing clock and can operate in intervals of one thousandth of a second, that is, one millisecond.

The top eight pins are for making the chip work. The next two are for providing the chip with electrical power. The bottom eight pins are separate outputs, any one of which can operate switches, timers, etc., just as the output from a 555 chip can. Having been named by computer people, instead of the eight output pins being numbered from 1 to 8 as any rational person would do, they have numbered them from 0 to 7.

The voltage on those output pins will be either High or Low. PIC switching can be used with a wide range of different free-energy designs. The PIC chip is generally supplied with a socket, a connecting cable and a program for feeding instructions into the chip. The feed is generally from an ordinary PC. The programming instructions are very simple and anyone can learn how to use them in just a few minutes.

So let’s look at a circuit which has been used by Jeff when he tests prototype circuitry. The first part of the circuit is for connecting the standard PC socket to the PIC chip and it looks like this:

A standard 9-pin computer socket has it’s pin 2 connected to the PIC’s pin 2, pin 3 connected to the PIC’s pin 3 via a 10K / 22K voltage divider resistor pair (which lowers the incoming signal voltage), and pin 5 is connected to the PIC’s pin 5. That is all that’s needed to feed information into the PIC chip.

The chip is supplied from a 12-volt battery but as it needs a 5-volt supply, the 100 / 150 ohm (2 watt) resistor pair is used to drop the 12 volts down to about 7 volts and then the 5.1-volt zener diode clamps the voltage at 5.1 volts, which is just what the chip needs. The tiny 10 nF (0.01 microfarad) capacitor is there to trap any voltage spikes should any be picked up from some outside influence. Finally, the press-button switch used to short between pins 4 and 5 is used to wipe out the program inside the PIC, ready for a new program to be loaded.

The actual programming is not difficult and the feed into the chip is handled by the program supplied with the chip and which is run on your home computer. Let’s take an example. Suppose we want the output on pin 10 to act as a clock signal. The people who made the chip expect that pin to be called “Output 4” in the program. Please don’t ask me why it isn’t called “10” in the program as I have no answer for you other than “it takes all sorts of people to make a world”.

All right, suppose we want to produce an output signal like a 555 chip running at 50 Hz. We choose one of our output pins, say, the physical pin 10, that being the bottom right hand pin on the chip. As you can see from the pin diagram of the chip shown above, pin 10 is called “Output 4” in a set of commands, or just “4” to save typing. The program might be:

    high 4
pause 10
low 4
pause 10
goto Main:

Wow – really difficult stuff !! Only a genius could manage to program! Well, we’ll see if we can struggle along with this “difficult” stuff.

The “Main:” at the start is a “label” which can be jumped to and that is done by the “goto Main” command which sends the chip back to repeat the commands in the loop indefinitely (or until the chip is powered down).

The second line “high 4” tells the chip to put the maximum possible voltage on the “Output 4” which is the physical pin 10 of the chip. The chip does this immediately, with no time delay.

If we want the output to give a 50 Hz output signal, then the voltage on our chosen output pin will have to go high, pause, go low, pause and go high again, 50 times each second. As there are 1,000 milliseconds in one second, and the chip’s clock runs with 1 millisecond ticks, then we need our complete cycle of “up, pause, down, pause” to happen 50 times in those 1,000 clock ticks. That is, once every 20 ticks, so each delay will be 10 clock ticks long.

The third line “pause 10” tells the chip to sit on it’s hands and do nothing for the next 10 ticks of it’s internal clock (which ticks 1,000 times per second).

The fourth line “low 4” tells the chip to lower the output voltage on it’s “Output 4” (pin 10 in real life) to it’s minimum value.

The fifth line “pause 10” tells the chip to wait for 10 milliseconds before doing anything else.

The last line “goto Main:” tells the computer to go back to the label “Main:” and continue with whatever instructions follow that label. This puts the chip into an ‘infinite loop’ which will make it generate that output waveform continuously. The output will look like this:

This gives an even waveform, that is, one with a Mark/Space ratio of 50:50 or a Duty Cycle of 50%. If we want the same rate of pulsing but a Duty Cycle of just 25% then the program would be:

    high 4
pause 5
low 4
pause 15
goto Main:

which produces this waveform:

If you wanted “Output 7” (physical pin 13) to do the reverse of this at the same time – that is, when Output 4 goes high we want Output 7 to go low, and vice versa, then, for a 20% Duty Cycle the program would be:

    high 4
low 7
pause 4
high 7
low 4
pause 16
goto Main:

These output voltages are then used in exactly the same way as the output voltages on pin 3 of a 555 chip, or any of the outputs of NAND gates, Hall-effect sensor chips, Schmitt triggers, or whatever. If the device to be powered requires very little current, then the easiest method is to connect the load directly to the output pin.

If, as is most often the case, the device to be powered needs a large current to make it work, then the output voltage is used to power a transistor, perhaps like this:

Here, the resistor “R1” limits the current fed into the base of the transistor when pin 10 goes high, but allowing enough current for the transistor to switch on fully, powering the load. The resistor “R” makes sure that the transistor switches off fully when the output on pin 10 goes low. The circuit as shown restricts the load to some piece of equipment which can operate on just five volts, so an alternative circuit could be:

This allows whatever voltage the load needs to be applied to the load, while the PIC chip remains running on it’s normal 5-volt supply. However, the equipment to be powered may not be able to have a common zero voltage connection with the PIC. To deal with this, an optical isolation chip can be used like this:

Here a high output voltage on pin 10 of the PIC chip lights up the LED inside the opto-isolator chip, causing a major drop in the resistance between the other two pins. This causes a current controlled by the resistor “R” to be fed into the base of the transistor, switching it on and powering the load.

Electronics Tutorial

The 741 Chip

The ‘741’ Chip
An important and very useful group of Integrated Circuits is the “Operational Amplifier” or “op-amp” group.   These devices have a very high gain, an ‘inverting’ input and a ‘non-inverting’ input.   There are many op-amps but we will look at just one popular type called the “741” which has an ‘open-loop’ gain of 100,000 times.   All operational amplifiers work in the same way in theory.   The way they operate in a circuit is controlled by the external components attached to them.   They can operate as inverting amplifier, a non-inverting amplifier (i.e. a ‘buffer’), a comparator, an astable multivibrator, and various other things.   The symbol and connections for a 741 op-amp are:

We can connect the 741 chip to act as an amplifier with any set gain level that we choose:

Here, the gain is set by the ratio of the 220K resistor to the 22K resistor.   This circuit has a gain of 10 times, so the input signal at point ‘B’ will generate an output signal at point ‘C’ which is ten times larger, provided that the output signal does not approach the battery voltage.   If it does, then clipping will occur with the top and the bottom of the output waveform chopped off at about a volt away from the battery voltage levels, approximately 1 Volt and +11 Volts in this example.

Operational amplifiers are generally designed to operate from a dual power supply.   In the above example, the supply would be created by using two 6 Volts batteries instead of one 12 Volt battery.   To avoid the inconvenience of this, a mid-point voltage is generated at point ‘A’ by using two equal resistors in series across the battery.   This gives a central voltage of +6 Volts which is fed to the IC.

This circuit can be used in many applications. Here is a circuit for a meter to measure sound intensity:

This circuit is two copies of the previous circuit.   Each 741 chip has a reference voltage of half the supply voltage created by a voltage-divider pair of 1K resistors.   This voltage is fed to pin 3 of the chip, which is the non-inverting input.

At point ‘A’, a microphone or small loudspeaker is used to generate a signal voltage when sound reaches it.   This voltage is fed to the 741 op-amp via a 1 microfarad blocking capacitor.   This passes the audio signal through while blocking the +4.5 Volts DC on pin 3.   The first 741 has a gain of 22, set by the 10K and 220K resistors (220/10 = 22).

Point ‘B’ then receives an audio signal 22 times larger than the signal produced by the microphone.   This signal is still quite small, so the second 741 boosts it further.   The gain of the second 741 is variable and depends on the resistance set on the 1M variable resistor.   If the variable resistor is set to zero ohms, then the gain of the second 741 will be controlled by the 4K7 resistor at point ‘C’ alone and so will be 1 (4.7/4.7 = 1).   If the variable resistor is set to its maximum value, then the gain of the second 741 will be some 214 (1,004,700/4,700 = 213.8).

The two op-amps together have a combined gain which ranges from 22 to 4702.   The amplified audio signal arrives at point ‘D’ and it can be adjusted to a respectable value.   This alternating voltage is now rectified via the diodes at point ‘E’ and it builds up a DC voltage across the 47 microfarad capacitor there.   This voltage is displayed on a voltmeter.   The result is that the voltmeter shows a reading directly proportional to the sound level reaching the microphone.

The 741 can be wired as a buffer.   This is the equivalent of an emitter-follower circuit when using transistors.   The set up for the 741 is:

Difficult circuit – huh! Are you sure you can afford all the extra components?   This circuit utilises the full gain of the 741 chip.   The output follows the input waveform exactly.   The input requires almost no current, so the circuit is described as having a ‘high input impedance’.   The output can drive a serious load such as a relay, so the circuit is described as having a ‘low output impedance’.

The 741 chip can be wired to act as a comparator.   This is the circuit:

Are you sure you are up to such a difficult circuit?   Bit complicated – huh!   This is the basic operational form for an operational amplifier.

If the voltage at point ‘A’ is higher than the voltage at point ‘B’ then the output goes as low as it can go, say 1 or 2 volts.

If the voltage at point ‘A’ is lower than the voltage at point ‘B’ then the output goes as high as it can go, say 10 volts or so.

Having seen how transistor circuits work, you should be able to understand why the 741 chip circuitry (which is a transistor circuit inside the 741 package) needs some voltage inside the supply rails to provide an efficient high-current output drive.

Here is a 741 version of the light-operated switch:

This circuit is set up as evening falls.   We want the relay to have minimum voltage across it in daylight, so the voltage at point ‘A’ needs to be higher than the voltage at point ‘B’.   As the 1K variable resistor is across the supply voltage, its slider can be set to any voltage between 0 Volts and +12 Volts.   To make this easy to do, we choose a ‘linear’ variable resistor as the logarithmic variety would be hard to adjust in this application.   With the ‘linear’ version, each 1 degree of rotation of the resistor shaft causes the same change in resistance, anywhere along the range.   This is not the case for the logarithmic variety.

Anyhow, we adjust the variable resistor downwards until the relay voltage drops to a minimum.   When the light level has fallen to the level at which we wish the circuit to trigger, we adjust the variable resistor to make the relay click on.   The 741 chip has a very rapid output voltage swing when the input voltages swap over, so the relay switching will be decisive.   The switching can be made even more positive by adding a resistor between the output and point ‘B’.   This acts like a Schmitt trigger when switching occurs by providing some additional positive feedback, lifting the voltage at point ‘B’.

If you wish the circuit to trigger on a rising light level, just swap the positions of the 10K resistor and the ORP12 light-dependent resistor.   The same circuit will operate as a temperature sensing circuit by substituting a ‘thermistor’ (which is a temperature-dependent resistor) for the ORP12.

If we would like the circuit to act as a burglar alarm, we could use the same circuit like this:

The circuit is still controlled by the voltage at point ‘A’.   Under normal circumstances, this voltage will be near +6 Volts (produced by the two 10K resistors and the 100K resistor).   The upper switch marked ‘NC’ for ‘Normally Closed’, represents a chain of, say, magnetic switches attached to doors and windows.   If any of these are opened, then the voltage at point ‘A’ will be dictated by the lower 10K resistor in series with the 100K resistor.   This will cause the voltage at ‘A’ to fall instantly to a low value, triggering the circuit.

The ‘NO’ switch (‘Normally Open’) represents one or more pressure-operated switches under carpets or rugs and/or switches which get brushed when doors are swung open, etc.   These switches are wired in parallel across each other and if any of them is closed for even a millionth of a second, the voltage at point ’A’ will be pulled down by the 1K resistor and the circuit will be triggered.

The circuit can be latched on in any one of a variety of ways.   One relay contact can be used to hold the relay on or hold the voltage at ‘A’ low.   A transistor can be wired across the relay to hold the circuit on, etc. etc.   If this is done, the circuit will remain in its triggered state until the supply voltage is interrupted.   You might prefer to use a 555 chip to limit the length of time the alarm sounds to three minutes or so.

An alternative to using a relay or semiconductor latch is to use a Silicon Controlled Rectifier usually referred to as an ‘SCR’ or ‘Thyristor’.   This device is normally “off” with a very high resistance to current flow.   If it is switched on by applying a voltage to its Gate connection, it stays continuously on until some external device stops current flowing through it.   The following circuit shows how it operates:

When the voltage is first applied to the circuit by closing switch S2, the SCR is in its OFF state so no current is supplied to the load. If the press-button switch S1 is pressed, a current is fed into the Gate of the SCR, turning it ON.   When switch S1 is allowed to open, the SCR remains in its ON state and it will stay that way until the current through it is cut off.   Opening switch S2 cuts off the current to the load and the SCR returns to its OFF state.   A very valid question would be: “Why have an SCR at all and just turn the load on and off with switch S2?”.   The answer is that switch S1 might be the under-carpet pressure pad of a burglar-alarm and it might be operated some hours after switch S2 was closed to activate the alarm system.   Stepping off the pressure pad does not stop the alarm sounding.

While this sort of DC latching action is useful, it is more common for an SCR to be used in an AC circuit.   For example, take the circuit shown here:

The 120 volt AC supply coming in from the right hand side, is converted to positive-going sine-wave pulses by the diode bridge.   This pulsing voltage is applied to the Load/SCR path.   If the voltage at pin 3 of the 555 chip is low, then the SCR will remain OFF and no current will be fed to the load device.   If the voltage on pin 3 goes high and the voltage applied to the Load/SCR chain is high, then the SCR will be switched ON, powering the load until the pulsing voltage drops to its zero level again some 1/120 of a second later.

The 555 chip is connected to form a monostable multivibrator and the timing components (the 120K resistor and the 10nF capacitor) cause it to output a 1 millisecond pulse which is long enough to trigger the SCR into its ON state, but short enough to have finished before the mains pulse reaches its zero-voltage level again.   The 555 chip is triggered by the rising mains voltage being passed to its pin 2 through the voltage-divider 100K and 120K pair of resistors, and that synchronises it with the AC waveform.   Pin 4 of the 555 chip can be used to switch the load power on and off.

In the circuit shown above, the diode bridge is needed to convert the incoming AC waveform to pulsing DC as shown in red in the diagram, as the SCR can only handle current flowing in one direction.   The AC load equipment works just as well with the pulsing DC as with a full blown AC waveform.   A better semiconductor construction is the ‘Triac’ which acts like two SCR devices back-to-back in a single package.   It is shown like this in circuit diagrams:

There are three connections to the device: Main Terminal 1, Main Terminal 2 and the Gate.   When switch ‘S’ shown in the diagram is closed, the triac conducts on both positive and negative voltages applied to its MT1 and MT2 terminals.   When the switch is open, the device does not conduct at all.

If the external circuit containing switch ‘S’ is placed inside the device as a permanently closed circuit, then the device becomes a ‘Diac’ which can be used to trigger a Triac and give a very neat circuit for controlling the power to an item of AC mains equipment as shown here:

Here, the variable resistor/capacitor pair controls the point on the AC waveform that the Triac is triggered and so controls how much of each sinewave cycle is passed to the mains equipment, and so it controls the average power passed to the equipment.   A very common use for a circuit of this type is the ‘dimmer-switch’ used with household lighting.

To return now to the 741 chip.   The 741 can also be used as an astable multivibrator.   The circuit is:

The rate of oscillation of this circuit is governed by the Resistor marked ‘R’ in the diagram and the capacitor marked ‘C’.   The larger the resistor, the lower the rate of oscillation, the larger the capacitor, the lower the rate of oscillation.

When the output goes high, capacitor ‘C’ charges up until the voltage on it exceeds the mid-rail voltage on pin 3, at which time the 741 output goes low.   The capacitor now discharges through resistor ‘R’ until the voltage on it drops below the voltage on pin 3, at which time the output goes high again.   The 10K resistor connecting the output to pin 3 provides some positive feedback which makes the 741 act quite like a Schmitt trigger, sharpening up the switching.

The same arrangement of resistor and capacitor applied to a Schmitt inverter or Schmitt NAND gate causes exactly the same oscillation:

If you would like to see additional ways of using 741 and 555 chips, I can recommend the excellent book “Elementary Electronics” by Mel Sladdin and Alan Johnson ISBN 0 340 51373 X.

Here is a very well tested and highly thought of, low-cost oscillator circuit, using a 74HC14 Schmitt inverter chip. It allows fine tuning control of the frequency and the pulse width produced. Three of the inverters are connected together to give a more powerful output current drive:

Electronics Tutorial

The NE555 Timer Chip

The ‘NE555’ Timer Chip
There is an exceptionally useful chip designated by the number 555.   This chip is designed to be used in oscillator and timer circuits.   Its use is so widespread that the chip price is very low for its capability.   It can operate with voltages from 5 Volts to 18 Volts and its output can handle 200 mA.   It takes 1 mA when its output is low and 10 mA when its output is high.   It comes in an 8-pin Dual-In-Line package and there is a 14-pin package version which contains two separate 555 circuits.   The pin connections are:

This device can operate as a monostable or astable multivibrator, a Schmitt trigger or an inverting buffer (low current input, high current output).

Here it is wired as a Schmitt trigger, and for variation, it is shown triggering a triac which will then stay on until the circuit is powered down (an SCR could be used just as well with this DC circuit):

And here, a monostable:

And here are two astables, the second of which has fixed, equal mark/space ratio and the first a high output voltage time determined by Ra + Rb and a low voltage output time determined by Rb (2:1 in this case):

Note:   The high leakage of large value electrolytic capacitors prevents them being used with high value resistors in timing circuits. Instead, use a smaller capacitor and follow the timing circuit with a “divide-by-N” chip to give accurately timed long periods. Not all 555 chips have a manufacturing quality sufficient for them to operate reliably above 20,000 Hz, so for the higher frequencies the chip needs to be selected after testing its actual performance.

We can also wire the 555 to give a variable mark/space ratio while holding the frequency of the oscillation fixed:

The output waveform changes drastically as the variable resistor is adjusted, but the frequency (or pitch of the note) of the output stays unaltered.

A variable-frequency version of this circuit can be produced by changing the 33K resistor to a variable resistor as shown here:

Here, the 33K resistor has been replaced by two variable resistors and one fixed resistor.   The main variable resistor is 47K in size (an almost arbitrary choice) and it feeds to a second variable resistor of 4.7K in size.   The advantage of this second variable resistor is that it can be set to it’s mid point and the frequency tuning done with the 47K variable.   When the frequency is approximately correct, the 4.7K variable can be used to fine tune the frequency.   This is convenient as the small variable will have ten times more knob movement compared to the main variable (being just 10% of its value).

Obviously, it is not necessary to have the fine-tuning variable resistor, and it can be omitted without changing the operation of the circuit.   As the 47K variable resistor can be set to zero resistance and the 4.7K variable resistor can also be set to zero resistance, to avoid a complete short-circuit between output pin 3 and the 50K Mark/Space variable resistor, a 3.3K fixed resistor is included.   In this circuit, the frequency is set by your choice of the resistor chain 47K + 4.7K + 3.3K (adjustable from 55K to 3.3K) and the 100nF (0.1 microfarad) capacitor between pin 6 and the zero volt rail.   Making the capacitor larger, lowers the frequency range.   Making the resistors larger, also lowers the frequency range.   Naturally, reducing the size of the capacitor and/or reducing the size of the resistor chain, raises the frequency.

One 555 chip can be used to gate a second 555 chip via its pin 4 ‘Reset’ option.   You will recall that we have already developed a circuit to do this using two astables and a transistor.   We also generated the same effect using four NAND gates.   Here, we will create the same output waveform using the more conventional circuitry of two 555 chips:

Both of the 555 circuits can be bought in a single 14-pin DIL package which is designated ‘556’.

There are many additional circuit types which can be created with the 555 chip.   If you wish to explore the possibilities, I suggest that you get a copy of the book “IC 555 Projects” by E.A. Parr, ISBN 0-85934-047-3.

All right, suppose that we want to design and build a circuit to do the same as Bob Beck’s pulser circuit mentioned in chapter 11. The requirements are to produce a square wave output pulsing four times per second using a 27 volt power supply, the circuit being powered by three small PP3 size batteries. An obvious choice for the circuit seems to be a 555 timer chip which is small, robust and cheap and a suitable circuit would appear to be:

This leaves us with choosing a value for the capacitor and the resistor. We need to pay attention to the fact that the circuit will be running on 27 volts and while the capacitor will not charge up to anything like that voltage, we still will pick one which will survive 27V. Looking on the local eBay shows that a pack of ten capacitors of 1 microfarad rated at 50V can be bought for just £1 including postage, so take that as the value for “C”. Looking at the 555 table of frequencies above shows:

Which indicates that to get the circuit switching four times per second (4 Hz) the resistor “R” will need to be somewhere between 100K and 470K. With my capacitor, 120K is about right.

While the switching frequency does not have to be exact, let’s aim at getting it correct. Most reasonably priced components have a tolerance of around 10% so we need to select our resistor/capacitor combination for the exact values of the actual components which we will use. For this, it is worth building the circuit on a solder-less ‘breadboard’, so looking on eBay again we find that a suitable small plug-in board can be bought and delivered for £3. It looks like this :

These type of boards allow ICs to be plugged in spanning the central divide, leaving up to five extra connections on every pin. Short lengths of solid-core wire can be used to connect between any two socket holes. This will allow us to plug in one of our capacitors and find what resistor (or what two resistors) make the circuit switch forty times in ten seconds.

However, if we go to and download the data pdf for the NE555 chip, we find that the maximum 555 chip voltage is quite limited:

This means that the chip is liable to burn out instantly if it is fed more than 16 volts. As we need to run our circuit on 27V this is a problem. As the 27V is being provided by three separate batteries, we could supply the 555 chip from just one of the batteries and run it on 9V which would be ok from the point of view of the chip as the table above shows that it can operate correctly with a supply voltage as low as 4.5 volts. The disadvantage of that arrangement is that one of the batteries will run down more quickly than the others and it would be nice to avoid that.

The table also shows that the current draw just to keep the 555 running can be anything from 6 to 15 milliamps. That is not a large current but the PP3 batteries have been chosen for their small size, allowing the whole circuit to be strapped to a person’s wrist. A quick search on the internet shows that cheap PP3 batteries have a capacity of 400 milliamp-hours and the very expensive alkaline types 565 milliamp-hours. These ratings are the “C20” values, based on the battery being discharged at a constant current over a period of twenty hours, which would be ten days of use if Bob Beck’s two hours per day protocol is followed.

This means that the ‘cheap’ batteries should not be discharged at more than one twentieth of their 400 mAHr rating, which is 20 mA. The expensive alkaline batteries should be able to be discharged at 28 mA for twenty hours.

Our current draw is made up of two parts. The first part is supplying the circuit with the current which it needs to run. The second part is the current flowing through the body of the user. This second part is limited by the 820 ohm resistor in the output line which limits that part of the current to a maximum of 33 milliamps (Ohm’s Law: Amps = Volts /Resistance). This neglects the body resistance and assumes that the output control variable resistor is set to minimum resistance, which is unlikely.

Checking these values shows that the 555 chip is liable to draw as much current as the circuit supplies through the output electrodes. However, let’s go ahead with the circuit, after all, we might decide to use rechargeable PP3 batteries which would overcome the need to buy new batteries every few days.

The first essential requirement is to provide the 555 chip with a voltage of, say, 10 volts when it is running in the completed circuit. That could be done with one of the voltage-stabiliser integrated circuits:

That is not a particularly expensive option, but those chips draw a current in order to provide the voltage stabilisation and an absolutely steady voltage is not needed by the 555 chip. Alternatively, we could use a resistor and a 10V zener diode:

But that method does waste some current flowing through the zener in order to provide the wanted voltage. The most simple method is to use a resistor and a capacitor:

Considerable care is needed when selecting the resistor value “R”. If the value is too low, then the voltage passed to the 555 chip will be too high and the chip will burn out. When selecting the resistor “R”, start with a higher value than expected and then substitute slightly lower value resistors while monitoring the voltage across the capacitor to make sure that it stays low enough. The resistor value can be assessed using Ohm’s Law. Assuming a current of about 6 mA, the voltage drop across the resistor being (27 – 10) = 17 volts, then a resistor of about 2.83K (as Ohms = Volts / Amps) which suggests that starting with a 4.7K resistor is likely to be ok, and then picking each lower standard resistor in turn until a satisfactory voltage across the capacitor is reached.

The capacitor could be 12V or 15V rated, but if one rated at a higher voltage is used, then if it is accidentally connected across the full 27V it will not be harmed in any way. The larger the capacitance, the better, say 220 microfarads which can be got for a few pence on eBay. If you want to play safe, you could connect a 12V zener diode across the capacitor. It will not draw any current under normal working conditions, but if anything should cause the voltage on the capacitor to rise, then it will fire up and hold the voltage down to a safe 12V level. I would be inclined to see the zener as being unnecessary, but the choice is always yours.

So what resistor power rating is needed? Well, if the resistor turns out to be a 2.7K and the capacitor voltage ends up as 9.5 volts, then the average voltage across the resistor is 17.5V which makes the current through it 6.48 mA and as Watts = Volts x Amps, the power rating needs to be 113 milliwatts, so the typical quarter-watt (250 mW) resistor should be perfectly ok. If two (nearly equal value) resistors in parallel are used to get some intermediate value of “R” then that increases the overall resistor wattage.

The output of the 555 chip is then used to drive the remainder of the circuit which operates at 27V. A BC109C transistor costs only a few pence, can handle the voltage and has a minimum gain of 200 although the gain can be anything up to 800 and a BC109 can handle the current quite easily. If you need to find out any of these things, then download a datasheet for the transistor from the internet.

The output of the 555 timer is on pin 3 and it can easily supply 200 mA which is far, far more current than we would ever need for this circuit. We can feed the 555 square-wave output to the 27V electrodes using a transistor:

As the transistor is made of silicon, the switch-on voltage is when the base voltage is about 0.7 volts above the emitter voltage. That means that when the transistor is switched on, the top of resistor “R1” will be at around 10 volts and the bottom of “R1” will be at about 0.7 volts, which means that the voltage across “R1” will be (10 – 0.7) = 9.3 Volts. When that voltage is present across “R1” we want it to feed sufficient current to the transistor to switch it on fully. The transistor supplies a 100K resistor (which will carry 0.27 mA when 27 volts is across it) and the electrodes which will have a minimum resistance of 820 ohms across them (causing a current of 33 mA through them). So, the transistor might have to supply about 33 mA maximum. The BC109C transistor has a minimum gain of 200 so the current flowing into the base needs to be 33 / 200 = 0.165 mA and the resistor which will carry that current when it has 9.3 volts across it is 56.3K. A somewhat smaller resistor will suit.

A commonsense check that the resistor calculation is correct is:
A 1K resistor carries 1 mA per volt and so will carry 9.3 mA with 9.3 volts across it.
A 10K resistor will carry one tenth of that amount, or 0.93 mA with 9.3 volts across it.
A 100K resistor will carry one tenth of that again, or 0.093 mA with 9.3 volts across it.
This indicates that for a current of 0.165 mA which is about twice the 100K current, a resistor of about half of 100K should be about the right value, so 56.3K looks correct.

Considering that the gain of 200 is the minimum and three or four times that is typical, we could perhaps choose to use a 47K resistor for “R1”

As the electrode current is likely to be considerably less than 33 mA and as the BC109C gain is likely to be very high, it could be quite difficult to get the transistor to switch off as it can operate on very tiny amounts of input current. To get it to switch on and off cleanly when the 555 output voltage is say, about 5 volts, (at which point the NE555 voltage will be changing very rapidly), “R2” is included. With it in place, the output voltage of the NE555 is divided between “R1” and “R2” in the ratio of their resistances. The situation we want is:

When The transistor is not switched on, it draws almost no current and so looks like a very high value resistor to the circuit. This allows the “R1” and “R2” resistors to act as a voltage-divider pair. This causes the voltage at point “A” to be determined by the ratio of “R1” to “R2” and the transistor can be ignored provided that the voltage at point “A” is below 0.7 volts. If the voltage at that point rises to 0.7 volts then the situation changes dramatically and Ohm’s Law no longer holds as the transistor is not a passive resistor but instead, is an active semi-conductor device. If the voltage at point “A” tries to rise further it can’t because the transistor base clamps it solidly there by appearing to be an ever lower resistor between the base and the emitter of the transistor. So for higher input voltages, resistor “R2” might as well not be there for all the difference it makes.

So, what value do we need for “R2” in order for the voltage at point “A” to be 0.7V when pin 3 of the NE555 reaches 5V? Well, that part of the circuit is acting in a resistive fashion and so Ohm’s Law can be used. The resistor “R1” is 47K and has 4.3 volts across it, which means that the current through it must be 0.915 mA. That means that “R2” has 0.7V across it and 0.915 mA flowing through it which means that it has a value of 7.65K. A standard 8.2K or 6.8K resistor could be used as there is nothing dramatically important about the 5V switching point. If you were fussed about getting exactly 7.65K (and you shouldn’t be), then you can get that value by combining two standard resistors, either in series or in parallel.

A common sense method of working out the value of “R2” is to use the fact that as the same current flows through them (no matter what that current happens to be), then the ratio of the voltage will be the same as the ratio of the resistors. That is: 0.7V / 4.3V = “R2” / 47K or “R2” = 47K x 0.7 / 4.3 which is 7.65K.

We have now reached the point where we can determine the resistor value needed to provide a reasonable voltage for the NE555 timer chip, the circuit being:

The “Rx” value is going to be fairly close to 270K so you can use that value when testing to find a suitable value for “R” (2.2K in my case). The capacitor across the NE555 chip should be as large a capacitance as is convenient, bearing in mind that the entire circuit, batteries, etc. is to fit into a small case to be strapped to a wrist. One way that the components could be positioned on the plug-board is:

Remember that when trying various resistors for “R” you need to start high at about 4.7K and the resulting voltage on the capacitor shows the voltage drop across your first resistor choice and so, the actual current being drawn by your particular NE555 chip. That calculated current will allow you to calculate the resistor value needed to give 10 volts or so, allowing your next resistor to be tested to be almost exact in value.

For checking the frequency produced by the circuit, any ordinary LED can be used as a temporary measure. It can be connected across the 100K ‘load’ resistor between the transistor collector and the +27V positive supply line. A current-limiting resistor is essential to stop the LED burning out instantly. If we allow a current of 5 mA to flow through the LED then since the current-limiting resistor has some 26.3 volts across it, then it’s value will be about 5.4K (1K would give 26 mA, 2K would give 13 mA, 3K would give 9 mA, 4K would give 6.5 mA) and so a 4.7K resistor works well. This LED and resistor are shown in the layout above. Please remember that if your BC109C transistor has a metal case, then that case is normally connected internally to the collector and so, care must be taken that the case does not short-circuit to anything else.

If it is considered important to maximise battery life by reducing the current draw to a minimum, then perhaps using an astable circuit might be a good choice. In common with most electronic circuits, there are many different ways to design a suitable circuit to do the required job. The BC109C transistor can handle the 27V and so we might aim at a current draw for the circuit of just 3 mA. If 2 mA were to flow through the astable transistors when they are switched on, then with 27V across them, the resistors would be 13.5K which is not a standard value. We might select 12K to give a 2.25 mA current, or 15K to give 1.8 mA. Either should be satisfactory. The circuit might then be:

As the voltage swing feeding the output transistor has now risen from 10V to 27V the voltage-divider resistors can now increase in value by 2.7 times, giving around 127K and 22.1K for these resistors. However, the situation is not the same as for the NE555 chip which can supply at least 200 mA at the voltage-high output level. Instead, the transistor becomes such a high resistance that it can be ignored, but the 12K remains in the path which supplies the base current for the output transistor and it will in fact, add to the upper resistor of the voltage-divider pair. So while a 100K resistor is shown, it is effectively 112K due to that extra 12K resistor between it and the +27V supply line. The astable transistors will be switching fast at the point where the output transistor changes state, so the output square wave should be good quality. The BC109C transistor can switch on and off a hundred million times per second, so it’s performance in this circuit should be very good. A test breadboard layout might be:

We now need to choose the timing components. For an even 50% duty cycle where each transistor is ON for half the time and OFF for half the time, the two timing capacitors can be the same size and then the two timing resistors will have the same value, in my case, 330K but it depends on the actual capacitors used.

Bob Beck’s design calls for the LED display to be running when the unit is switched on and then be disconnected when the electrodes are plugged into a 3.5 mm socket mounted on the case containing the circuit. The switched socket looks like this:

When the plug is not inserted into the socket, pin 1 connects to pin 2 and pin 3 is not connected to anything. When the plug is inserted, then pin 1 is isolated, pin 2 is connected to plug pin 4 and pin 3 is connected to plug pin 5.

The Beck circuit is connected to the output socket like this:

This arrangement will give a 27V 4Hz square wave output through the jack socket. But, Bob Beck’s original circuit did not do that. Instead, it was like this:

Here, a relay operates two change-over switch contacts which are used to reverse the battery bank contacts four times per second. That is different from just producing a positive-going square wave voltage between the two output terminals. If you were to consider a resistor connected across the output socket, then with the relay switching, the direction of the current reverses four times per second, but with the square wave, while it starts and stops four times per second, the direction of the current is always the same and there is no reversal of direction.

As Bob wanted to avoid using a relay which clicks four times per second all the way through the two-hour treatment described in chapter 11 and in the “Take Back Your Power” pdf on the web site, he redesigned the circuit using the very impressive LM358/A integrated circuit:

This chip draws only half of one milliamp, has two very high-gain operational amplifiers and can operate with a wide range of supply voltages. It is also inexpensive.

Bob displays the circuit as:

Bob states that the first section acts as a 4Hz square-wave signal generator, the frequency being controlled by the 2.4M resistor “R1” and the 100nF capacitor “C1”. The data sheet for the LM358 states that the output voltage swing is between zero volts and 1.5V less than the supply voltage “Vcc” (which is +27V in this case). That implies that, as would be expected, the pin 1 output voltage from the first stage will switch sharply from 0V to +25.5V and sharply back again, four times per second.

It is difficult to follow the circuit as it is drawn, so it might be a little easier to follow when drawn like this:

The output from the first amplifier inside the LM358 package is on pin 1 and it can supply a large amount of current (if a large current is ever needed). That output goes straight to one of the jack socket connections. It also goes the pin 6 input of the second amplifier inside the chip and that causes the high-power output of that amplifier on pin 7 to be the opposite of the pin 1 voltage. When pin 1 goes high to +25.5 volts, then pin 7 goes low, to about zero volts. That output is also fed to the other jack socket connection, placing 25.5 volts across the electrodes when they are plugged in to the jack socket.

When the oscillator circuitry connected to the first amplifier causes the voltage on pin 1 to go low, then the output on pin 7 inverts it and so it goes to +25.5 volts. You will notice that while the overall voltage of 25.5 volts is applied again to the jack socket, the polarity is now reversed, achieving what the relay circuit does (although 1.5 volts is lost in the process). This is a neat solution.

Bob uses a two-colour LED to confirm that the circuit is working correctly before the electrodes are plugged in. He chooses to do it this way:

The two 18V zener diodes drop off 18.7 of the 25.5 volts as one will be forward biased dropping 0.7 volts and the other reversed biased, dropping off 18 volts. That leaves a 7V drop for the LED, which is a bit excessive, so Bob says that he uses a capacitor to limit the current. As there is already an 820 ohm resistor in the LED current path through the socket, the capacitor is not needed. The variable resistor need to be set to it’s minimum resistance by rotating it’s shaft fully clockwise so that it does not affect the LED brightness as the zeners also show when the battery voltage has dropped as there will no longer be sufficient voltage to light the LED brightly, indicating that the batteries need to be replaced (or recharged if they are rechargeable batteries). When testing the circuit, an alternative to the two zeners is to use a 4.7K resistor and if a bi-colour LED is not to hand, then two ordinary LEDs can be used back to back like this:

With this arrangement, the two LEDs flash alternately. In any circuit, a capacitor with a higher voltage rating can always be used if the capacitance values are the same. The Beck external circuit is completed through the body of the user, so there is just one electrode connected to each side of the output jack socket. A possible plug-board layout is:

The 4.7K resistor and LEDs are only on the board for testing purposes and when the circuit is built in permanent form, then the LED chain connects to pin 1 of the jack socket so that the LEDs are disconnected during the two hours of daily treatment recommended when using the device.

One stripboard layout using the standard 9-strip 25-hole board and incorporating the two 18V zener diodes for voltage sensing is:

When using a Beck device, it is very important to pay attention to the precautions which Bob sets out. These are in his “Take Back Your Power” pdf document: which includes the following, which, while it refers to treatment to deal with HIV, presumably applies to all treatments with his device:


HYPOTHETICAL PROTOCOLS FOR EXPERIMENTAL SESSIONS Revision March 20, 1997. Copyright 8 1991/1997 Robert C. Beck

PRECAUTIONS: Do NOT use wrist to wrist current flow with subjects who have cardiac pacemakers. Any applied electrical signals may Interfere with ‘demand’ type heart pacers and cause malfunction. Single wrist locations should be acceptable. Do NOT use on pregnant women, while driving or using hazardous machinery.

Users MUST avoid Ingesting anything containing medicinal herbs, foreign or domestic, or potentially toxic medication. nicotine, alcohol, recreational drugs. laxatives, tonics. and certain vitamins etc., for one week before starting because blood electrification can cause electroporation which makes cell membranes pervious to small quantities of normally harmless-chemicals in plasma. The effect Is the same as extreme overdosing which might be lethal. See Electroporation: a General Phenomenon for Manipulating Cells and Tissues; J.C. Weaver, Journal of Cellular Biochemistry 51:426-435 (1993). Effects can mimic increasing dosages many fold. Both the magnetic pulsar and blood purifier cause electroporation.

Do NOT place electrode pads over skin lesions, abrasions, new scars, cuts, eruptions, or sunburn. Do NOT advance output amplitude to uncomfortable levels. All subjects will vary. Do NOT fall asleep while using. The magnetic pulser should be safe to use anywhere on body or head.

Avoid ingesting alcohol 24 hours before using. Drink an 8 oz. glass of distilled water 15 minutes before and immediately following each session end drink at least four additional glasses daily for flushing during ‘neutralization’ and for one week thereafter. This Is imperative. Ignoring this can cause systemic damage from unflushed toxic wastes. When absolutely essential drugs must be ingested, do so a few minutes after electrification then wait 24 hours before next session.

If subject feels sluggish, faint, dizzy, headachy, light-headed or giddy, nauseous. bloated or has flu-like symptoms or rashes after exposures, reduce pulsing per session and/or shorten applications of electrification. Drink more water-preferably ozonized -to speed waste oxidation and disposal. Use extreme caution when treating patients with impaired kidney or liver function. Start slowly at first like about 20 minutes per day to reduce detoxification problems.

To avoid shock liability, use batteries only. Do NOT use any line-connected power supply, transformer, charger, battery eliminator, etc. with blood clearing device. However line supplies are OK with well-insulated magnetic pulse generators (strobe lights).

Health professionals: Avoid nicotine addicts, vegans, and other unconsciously motivated death-wishers and their covert agendas of ‘defeat the healer’. Tobacco, the most addictive (42times more addictive than heroin) and deadly substance of abuse known, disrupts normal cardiovascular function. True vegetarian diets are missing essential amino acids absolutely necessary for the successful rebuilding of AlDS-ravaged tissues. Secondary gains (sympathy / martyrdom, work avoidance, free benefits, financial assistance, etc.) play large roles with many AIDS patients. “Recovery guilt” as friends are dying has even precipitated suicide attempts masked as ‘accidents’. Avoid such entanglements, since many have unconscious death wishes.

SUPERIOR ELECTRODES: Excellent, convenient and vastly superior electrodes, reusable indefinitely can be made by butt-soldering lead wires to ends of 1” long by 3/32” dia. blanks cut from type 316 stainless steel rods available from welding supply stores (Cameron Welding Supply. 11061 Dale Ave., Stanton, CA 90680). Use ‘Stay Clean’ flux before soldering (zinc chloride/hydrochloric acid). Shrink-insulate TWO tight layers of tubing over soldered joints to prevent flexing/breaking and lead/copper ions from migrating. Wrap three or four turns of 100% cotton flannel around rods. Spiral-wrap with strong thread starting from wire side to end, tightly pinch cloth over the rod’s end so as to leave no metal exposed by wrapping 6 or 7 turns of thread TIGHTLY just off end of rod, then spiral wrap back to start and tie tightly with four knots then cut off excess cloth at end close to pinch -wraps. Treat end windings and knots with clear fingernail polish or Fray Check® (fabric & sewing supply stores) to prevent ravelling. Soak in a strong solution of sea salt (not table salt) containing a little wetting agent like Kodak Photo Flow, ethylene glycol, or 409 kitchen cleaner. Add a few drops of household bleach, sliver colloid, etc., for disinfectant. Store solution for reuse. Tape soaking-wet electrodes tightly over pulse sites with paper masking or Transpore™ tape or with 1”wide stretch elastic bands with tabs of Velcro ® at ends to fasten. Electrodes should closely conform precisely along blood vessels, not skewing ever so slightly over adjacent flesh. This insures better electrical conductivity paths to circulating blood and insures very low internal impedance. (~2000W). Rinse and blot-dry electrodes and skin after each use. NEVER allow bare metal to touch skin as this will cause burns manifested as small red craters that heal slowly. The objective is to get maximum current into blood vessels, not leak it over to adjacent tissue. Therefore never use any electrode wider that about 1/8 inch (3 mm).

ELECTRODE PLACEMENTS: Locate maximum pulse position (NOT to be confused with acupuncture, reflexology, Chapman, etc. points) on feet or wrists by feeling for maximum pulse on inside of ankle about 1”below and to rear of ankle bone, then test along top centre of instep. Place electrode on whichever pulse site on that foot that feels strongest. Scrub skin over chosen sites with mild soap and water or alcohol swab. Wipe dry. Position the electrodes lengthwise along each left and right wrists blood vessel. Note: with subjects having perfectly healthy hearts and not wearing pacers, it is convenient to use left wrist to right wrist exactly over ulnar arterial pulse paths instead of on feet. Recent (Dec. 1995) research suggests that placing both electrodes over different arteries on the same wrist works very well (see pg. 7), avoids any current through heart, and is much more convenient and just as effective. An 8” long, 1” wide elastic stretch-band with two 1.5” lengths of 3/4” wide Velcro ® sewn to ends of opposite sides makes an excellent wrist band for holding electrodes snugly in place. With electrode cable unplugged, turn switch ON and advance amplitude control to maximum. Push momentary SW. 2 ‘Test’ switch and see that the red and green light emitting diodes flash alternately. This verifies that polarity is reversing about 4 times per second (frequency is NOT critical) and that batteries are still good. When LED’s don’t light replace all three 9V batteries. Zener diodes will extinguish the LEDs when the three 9V battery’s initial 27V drops below 18V after extended use. Never use any electrode larger than 1.125” (28 mm) long by 1/8” wide to avoid wasting current through surrounding tissue. Confine exactly over blood vessels only. Apply drops of salt water to each electrode’s cotton cover ~every 20 minutes to combat evaporation and insure optimum current flow. Later devices are solid-state, use only three batteries and no relays, and are much smaller.

Now rotate amplitude control to minimum (counter-clockwise) and plug In electrode cable. Subject now advances dial slowly until he feels a “thumping” and tingling. Turn as high as tolerable but don’t advance amplitude to where It is ever uncomfortable. Adjust voltage periodically as he adapts or acclimates to current level after several minutes. If subject perspires, skin resistance may decrease because of moisture, so setting to a lower voltage for comfort is indicated. Otherwise it is normal to feel progressively less sensation with time. You may notice little or no sensation at full amplitude immediately, but feeling will begin building up to maximum after several minutes at which time amplitude must be decreased. Typical adapted electrode-to-electrode impedance is on the order of 2000W. Typical comfortable input (to skin) is ~3mA, and maximum tolerable input (full amplitude) is about7mA but this ‘reserve’ margin although harmless is unnecessary and can be uncomfortable. Current flowing through blood Is very much lower than this external input because of series resistance through skin, tissue and blood vessel walls, but 50 to 100 µA through blood is essential.

Apply blood neutralizer for about 2 hours daily for about2 months. Use judgment here. The limiting factor is detoxification. Carefully monitor subject’s reactions (discomfort, catarrh, skin eruptions, weeping exudites, rashes, boils, carbuncles, coated tongue, etc.). With very heavy infections, go slower so as not to overload body’s toxic disposal capability. With circulation-impaired diabetics, etc., you may wish to extend session times. Again, have subject drink lots of water. Recent changes in theoretical protocol being currently tested suggest following up the three weeks of treatments with a 24 hours per day (around the clock) continuous electrification of blood for two days to deal a knockout blow to the remaining HIV ’s 1.2 day life cycle. (A. Perelson; Los Alamos Biophysics Group, Mar. 16, 1996 “Science” Journal.) Remember to remoisten electrodes regularly. If you absolutely must ingest prescription drugs, do so immediately after turning off instrument and allow 24 hours before next treatment to let concentrations in blood plasma decay to lower levels.

Remember, if subjects ever feel sleepy, sluggish, listless. nauseous, faint, bloated, or headachy, or have flu-like reactions they may be neglecting sufficient water intake for flushing toxins. We interpret this as detoxification plus endorphin release due to electrification. Let them rest and stabilize for about 45 minutes before driving if indicated. If this detoxing becomes oppressive, treat every second day. Treating at least 21 times should ‘fractionate’ both juvenile and maturing HIV to overlap maximum neutralization sensitivity windows and interrupt ‘budding’ occurring during HIV cells’ development cycles. Treatments are claimed to safely neutralize many other viruses, fungi, bacteria, parasites, and microbes in blood. See patents US 5,091,152 US 5,139,684 US 5,188,738 US 5,328,451 and others as well as numerous valid medical studies which are presently little known or suppressed. Also. ingesting a few oz. of about 5 parts per million of silver colloid solution daily can give subjects a ‘second intact immune system’ and minimise or eliminate opportunistic infections during recovery phase. This miracle substance Is pre-1938 technology, and unlike ozone is considered immune from FDA harassment. Silver colloid can easily be made at home electrolytically in minutes and in any desired quantities and parts per million strength for under 14 cents per gallon plus cost of water. It is ridiculous to purchase it for high prices. Colloid has no side effects, and is known to rapidly eliminate or prevent hundreds of diseases. Sliver colloids won’t produce drug resistant strains as will all other known antibiotics. No reasonable amount can overdose or injure users either topically, by ingestion, or medical professional injection.

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