Hulda Clark

How to build a Syncrometer

Here are two excerpts from the video Syncrometer Basics. Carmen Myers shows how to test a home made Syncrometer, and then Dr. Clark demonstrates how to use it. For more information on building and using this interesting audio oscillator circuit, read The Syncrometer Science Laboratory Manual.

Excerpt from Hulda Clark's book, The Cure For All Cancers, pages 454-468


If you are new to electronics you will need to know what a lead is. A lead is simply a wire used to connect two parts electrically. The method of clipping the lead to the component (part) determines its name. An alligator clip test lead uses a small metal clothespin for connecting, while a mini-hook clip lead is like a small, spring-loaded crochet hook. The mini-hook is best for attaching to a wire, the alligator clip is best for larger connections like to the test surfaces.

Leads come in many different lengths and are carried by all electronics stores.

The testing device consists of four parts: the test surfaces, probe and handhold, speaker, and circuit. These are connected by leads. The first item to construct is the test surfaces.

Syncrometer test surfaces

Test Surfaces

You will need two plates to set test samples on. The plates that hold the samples are intentionally separated from the main circuit because, unless you add shielding, the frequencies on the test plates may interfere with the circuit.

Materials needed:

Acceptable: Cut two 3 1/2 inch squares out of stiff paper such as a cereal box. Cover them with slightly larger squares of aluminum foil, smoothed evenly and tucked snugly under the edges. You have just made yourself a set of open capacitors.

Mount two ordinary light switches on the front side of the shoe box, one in front of each plate. Cut 1 by 1/2 inch rectangular holes to let the toggle through. Remove the screws that came with the switch, then insert the switch from inside so that OFF is when the toggle is UP (this is the reverse of how most light switches are oriented). Push a pin from the inside thorough the screw holes, enlarge them, and replace the screws from the outside. If the shoe box is too shallow, flex the "ears" off the switches.

On the shoe box, label the left plate "Substances" and the right plate "Tissues". Label the toggle for each plate with an "OFF" and "ON".

Using a short alligator clip test lead, attach the tissue plate bolt to the tissue switch at one screw terminal. If there are three screw terminals, one will be green for ground - do not use it, use the other two. Attach the other screw terminal on the tissue switch to the substance plate bolt. Attach the substance plate bolt to the substance switch at one screw terminal. Finally attach a long alligator clip test lead to the other substance switch screw terminal. The other end will be attached to the circuit when you build it.

Choose either the "Acceptable" or the "Best" construction technique. You do not have to do both.

Best: Use a large plastic project box instead of the shoe box. Do not use project boxes with metal lids. If you can not find all plastic boxes, remove the metal top and mount the test plates to the bottom. Use insulating sleeves and solder all connections.

Syncrometer Probe and Handhold

Probe And Handhold

These are what you grasp when testing. The places to attach the probe and handhold are described with the circuit instructions.

Acceptable: For the probe use an empty ball point pen (no ink) with a metal collar by the point. Connect a two or three foot alligator clip test lead to this collar. For the handhold use a cheap metal can opener (the kind that fills your hand) with a second alligator clip test lead attached.

Best: The Archer Precision Mini-Hook Test Lead Set has a banana plug for the probe on one end and a mini-hook on the other end for easy attachment to the circuit. Tape a long, new pencil to the probe; this makes it easier to hold. The best handhold is simply a 4 inch piece of 3/4 inch copper pipe (which a hardware store would just saw off for you) connected to the circuit with a three foot alligator clip test lead.

Banana Plug Probe = Radio Shack #278-1160A Precision Mini-Hook Test Lead Set

Syncrometer speaker


Hearing is believing. The sound made when you test substances lets you know if you have a YES (positive) or NO (negative). The better the sound quality the easier it is to hear the difference.

Acceptable: You may hook the circuit up to your stereo system. Make sure you ask an expert to make the attachment. The leads (wires) you need to do this depend on the terminals your stereo has, but the end of the lead to the circuit should have either alligator clips or mini-hooks for easy attachment. Turn the bass all the way down, and the treble all the way up when you use it. Headsets do not work.

Best: The Archer Mini Amplifier Speaker is inexpensive and small (about the size of a transistor radio), making it easy to take with you. It needs a 9 volt battery. Remove the screw at the center back of the speaker using a Phillips screw driver to gain access to the battery compartment. Also get an 1/8 inch phono jack. Plug the phono jack into the receptacle marked "INPUT", and unscrew the plastic housing on the jack to expose the two posts for attaching wires. Each post should have a small hole in it to attach a mini-grabber lead. If there are no holes use alligator clip leads, but slip a piece of plastic tape between the posts to make sure the alligator clips do not touch each other.

You are now ready to build the main circuit.

Materials needed:

Syncrometer main circuit

Parts List

Item Radio Shack #
Ordinary light switch
Potentiometer (variable resistor), 50k ohms 271-1716
Knob to fit potentiometer 274-428
.1 micro farad ceramic disk capacitor 272-1432A
.0047 micro farad ceramic disk capacitor (.005 will do) 272-130
MPS2907 PNP silicon transistor or equivalent 276-2023
Audio output transformer 900 CT: 8 ohm 273-1380
3 size AA batteries
Battery holder for 4 AA's (3 AA battery holder will do) 270-391 has 2 wires coming away from it, one red (for +), one black (for -).
Microclip test jumpers 278-017 (you need 6 packages of two)

Paste this in the box


  1. Get a shoe box, save the lid, print the picture above and tape it to the bottom (inside) of the box.
  2. Mount the light switch (a) just like you did for the test plates on the front of the shoe box. Mount it in the regular way so that ON is UP and label the box clearly. Turn light switch OFF before continuing.
  3. Pierce a hole with a large nail or pencil for the shaft of the potentiometer (b), and a smaller hole for the tab on the side of the potentiometer (the tab keeps the potentiometer from rotating when you turn the switch). Remove the nut and washer from the base of the potentiometer shaft, insert the shaft into the hole from inside of the shoe box. Trim the excess cardboard around the shaft with a knife. Replace the washer, nut and tighten securely.
  4. Attach the knob (c) to the shaft. Use a very small screw driver or pointed knife to tighten.
  5. Pierce holes in the box with a pin for the .1 micro farad capacitor (d) and the .0047 micro farad capacitor (e). Push the wires of each capacitor through the holes from the outside. When the ceramic part is almost touching the box, bend the wires inside to keep it in place. The capacitors look very much alike, so be careful not to switch them (open one capacitor package at a time and put the part directly in place, double checking the diagram).
  6. Pierce the holes for the transistor (f). Examine the transistor. Hold it in your left hand with the flat side on the let and wires pointing up at you. Notice that the center wire is the "base". Bend the base wire away to the left slightly so you will be able to insert the transistor into the triangle of holes. A diagram on the transistor package tells you that the top wire is the "collector" and the bottom wire is the "emitter". Insert the transistor from the outside of the box so each wire goes where it is supposed to=, and bend the wires sideways to secure.
  7. Pierce seven holes for the transformer (g). There should be 2 wires on one side and 3 on the other. All wires should have the ends bared and available for connections. If they are not, strip away 1/4 inch of insulation and twist the strands together on each wire to keep them neat (practice using the wire stripper, first on a different piece of wire). Notice that the transformer has 2 little mounting tabs. Push them through the box and bend them down with a knife or screwdriver on the inside to keep the transformer firmly in place or tape the transformer to the outside of the box. Then thread the 5 wires through their respective holes.
  8. Prepare the battery holder (i) by cutting the wires to no more than two inches. Bare the ends of the wires for 1/4 inch. You will only use three batteries, so in one of the battery slots, fill the space with a paper clip. Straighten one end of the paper clip. Hook the other end to the spring, and thread the straight part though the hole on the other side. Then bend the straight part down on the outside, out of the way.
  9. Next, insert three AA size batteries (h) in the holder (i) (note the plus (+) and minus (-) ends are marked on the holder). Notice that one wire is red (for positive) and one is black (for negative). Don't let the bared ends of the two wires touch. Pierce the holes for the battery wires and insert from the outside. Tape the battery holder to the outside of the box. If your batteries get warm remove them and recheck your connections. Now to connect everything.
  10. Use 9 microclip test jumpers (j) to make the nine connections drawn. Note that connection 6 needs an alligator clip lead to the light switch. Pull on each connection after you make it, and stuff the extra wire through a slit made in the side of the she box with scissors. Make slits wherever you need them. Then clip the lead from your test plate shoe box to the capacitor where shown. Next attach the probe and handhold where shown. Finally attach the speaker where shown. In the picture there are both mini-hook and alligator clips depicted, but it is not important which kind you use, only that you make secure connections.
  11. Test the circuit. Turn the speaker on, and the volume half way. Turn the Syncrometer (light switch) ON. Test the circuit by briefly touching the probe to the handhold. The speaker should produce a should like popping corn (readjust speaker volume to a comfortable level). If you hear nothing, go over each step carefully. Make sure the batteries are fresh. Recheck all connections, especially ones made to stripped wires. Replace the lid and turn the shoe box over so it sits on its lid.
  12. Label the potentiometer. Turn the knob almost fully clockwise. Mark the box where the line on the knob points. Grasp the handhold in one hand and press the probe with your thumb. Listen to the pitch. Now turn the knob almost fully counterclockwise, mark the box, and listen to this pitch. Whichever pitch is higher label MAX (maximum) on the box.
  13. You did it! Turn off the speaker and the Syncrometer.

Hulda Clark Syncrometer

After you have used the Syncrometer for a while you may wish to take your device to an electronics shop and ask someone to mount the components in an all plastic box and solder the connections. This would let you travel with it in your suitcase without mashing it into a jumbled mess of wires.

Syncrometer Schematic

Syncrometer schematic