ASSEMBLING A Hulda Clark's ZAPPER (or two ...)
I receive, time to time, questions about building a simple, functional zapper of the Hulda Clark's style, from
scratch, step by step. This zapper MOST follow the guidelines established by Dr. Clark (see details here).
Here is the original Hulda Clark’s zapper schematic, as our starting point.
Original Dr. H. Clark’s zapper
For the record, here are the most
important points on a Hulda
1_ "Any positively offset
frequency (DC) ..."
2_ A working frequency of "...
(anything from 10Hz to 500
3_ "... giving sufficient voltage 5
4_ Output current limited to 3mA
/4mA peak (Internal resistor of
5_ DC offset of at least 0,25V at
any time, to be sure rule_1 is
Making a parenthesis… :
If you want to build a Hulda Clark's zapper yourself, I see two main motivations :
1_ Buying a zapper is problematic (for financial reasons, or zappers are not available locally, or
2_ You want to experiment with different versions, and want to have a basic example, where to start with
on your experiments.
I will give you two starting points, meeting these motivations:
1_ A zapper easy to build, as cheap as possible, with the fewest possible number of components.
This zapper’s example is a everybody’s challange on its root version :
Are you able to do better (cheaper, simpler), while respecting Dr. Clark’s criteria ?
If yes, please let me know your findings, and if they are legitimate (I am the only judge), I will publish your
version, for the benefit of all and everybody.
Note: CD4585 CMOS circuit also allows a simple assembly, but lacks the robustness of the 555, for an
2_ The second example of a zapper build step by step takes the MZ4_TN1, as a starting point, for a
modern, up-to-dated zapper.
In the meantime, here is the “ultra-
simple” version, meeting all the
recommendations of Dr. Clark.
This is a challenge :
Can you to do better?!
Short lis of material
Resistors 1/8W or more
Capacitor 16V or more
U1: 7555 (CMOS)
IN-G1 (input) 9V battery connector
OUT_G2 (Output) Leads with alligator
The frequency of this assembly, with nominal values, will be (approximately) 30kHz (20kHz to 40klHz is good)
If you want other frequencies, C1 and R1 are the components to change.
In this design, the frequency has a duty cycle ratio of 50/50.
The formula to calculate the frequency is (approximately): Fr (Hz) = 0.722/ R1 (M_Ohms) x C1 (uF)
and R1(M_Ohms)= 0.722/ Fr(Hz) x C1(uF) and C1(uF) = 0.722/ Fr(Hz) x R1(M_Ohms)
30kHz ~ = R1= 200k & C1 = 120pF 2.5kHz ~ = R1= 290K & C1 = 1.0nF
15Hz ~ = R1= 220k & C1 = 0.22uF 7.83Hz ~ = R1= 422K & C1 = 2.2nF
Not Critical: Frequency can vary with the battery’s voltage and the load.
Resistance R2 (mandatory) = 1k_Ohm protects the zapper ... and the user.
The capacitor of 0.1uF or 0.01uF, usually connected to pin_5 provides greater frequency stability, which
is non-essential in a zapper (A little wobble of the frequency is even desirable)
This set-up is more a challenge then a practical and desirable zapper :
= Having to install or remove battery’s clip connector to run the zapper is not very convenient.
= A “ON” indicator would be welcome.
= Making an unwanted contact reverse side, with the battery for only a few seconds can (and will) destroy
your zapper, because it is not protected agains this quite common mistake.
For all these reasons, we will design a more practical version with these features, costing only $1 or $2.00
IF a WIND OF MADNESS BLOWS
And you decide to add a 30% on your
budget, getting away of the “simplest
zapper’s in the world” (everything is
relative (:-), you can add (in the same
spirit of simplicity), for about 1 or 2
dollars / Euros
= A ON-OFF switch
= A diode protecting your precious
device against connection errors, when
changing the battery (smoke signals
can occur very quickly, otherwise)
= A "multi-function" LED indicator.
Ho-Ho-Ho! The simplest
zapper in the world?
And it works?
As well as the original?
The LED, as featured here, has 3 different and interesting functions:
a) The LED lights when the zapper is on (usual).
b) Because of its clever placement, the LED will light brighter, when the load (you) is well connected,
providing a valuable indication of "zapper well connected", working as spected.
On 15Hz frequency, you will notice a flickering of the light : Normal : You can "see" 15Hz, but not 30kHz.
This LED decreases by about 2V the “peak to peak” output voltage, which still leaves enough variations of
voltage available - equivalent to the original zapper (not bad!).
Its strategic position does not reduce the maximum peak voltage output (important).
c) This LED, on top of all this, will perform an unexpected task: It will produce an offset of about 1.5 to
2V without load, which is a great news!
The resistor R3 in the ZWS01 diagram is no longer needed. Yippee!
The protection diode D1, through its strategic position, will protect the assembly against possible reversals
of the battery (even momentary), without removing the maximum peak voltage at the output. The diode will
add another 0.5V to the offset of the LED, which is not a dramatic issue.
Values for different frequencies given in the previous schematic (ZWS01) are still valid.
Good knowledge of electronic and electronic assembly is strongly recommended
You'll need a soldering iron, solder, and some common tools for electronicians.
The end result will be better checked with an oscilloscope.
1_ The simplest zapper in the world?
2_ A very simple zapper : THEORY
3_ A very simple zapper : PRACTICE
The next page will deal with an improved version of the MZ4_TN1, who will have
little to envy to the popularly expensive UZ ($189.00)
Coming in a next “rainy day” with some spare time ...
Bill of material
I give you this list with some references to DigiKey. Their prices are a good reference (you could find
cheaper). Their shipping costs and speed of shipping are good. Free, unwanted publicity.
Other local suppliers can certainly provide the same components (or equivalents) without problem.
DK references shows you what it's all about, but are not an obligation.
Resistors: 1/6W is enough. More will not hurt. Accuracy 5% or better. The least expensive will do.
Capacitors: 16V is enough. More will not hurt. 20% accuracy or better. The cheapest will do.
The 555 should be a CMOS version. Not the bipolar kind (NE555).
Only alternative: TLC555
Alternative: 1N4001 to 1N4004
LED: High intensity: LTL2R3KFK DK: 160-1683-ND or equivalent
9V connector: DK: BS6I-HD-ND or equivalent
3 feet red wire or equivalent, AWG # 18 to AWG # 24 (junk)
1 meter black wire or equivalent, AWG # 18 to AWG # 24 (junk)
1 Black alligator clip: DK: CP-2410-ND or equivalent
1 Red alligator clip: DK: CP-2411-ND or equivalent
A slide switch or toggle switch 2 positions (Too expensive on DK, look locally for about $1 or $2 )
1 piece of proto PCB (Too expensive on DK, look locally for about $1 or $2 )
1 plastic enclosure (optional)
Circuit assembly :
"1 ounce of planning worth 5 pounds of
Here's what I want to do.
Assembly : Back to the working bench!
Mainly from my junk box ...
Most of these pieces were lying
"discarded" from current use
The 2 PCB’s on the bottom left, show
the origin of the used circuit (top
Wires are old, long test jumpers.
Nominal, theoretical numbers :
= Output frequency : 30kHz.
= With a 9V battery, I expect to get 9V
= With any battery voltage, I expect to
have 2.3V offset (Diodes = 1.8V +0.5
V), so a peak-to-peak signal of 7.7Vptp
- without charge is also expected.
The LED should turn on slightly with the
passage of current in the 7555, and
should go brighter when under load.
The drawing at left, shows the location
of every component.
The drawing at right, shows an example
to follow (direct view, solder side) for
the connections on the solder side.
Here's the new-born zapper.
Expect a few assembly problems,
normal in this kind of prototyping work.
= Note the notched circuit in the
bottom left, to accommodate the LED,
flat on the board.
= The switch was fixed with a blob of
epoxy, to the circuit. Hot glue should
= All the wires will be tight later on with
a “Tye Wrap", to the board.
= A heat shrinkable plastic tube will be
installed at the very end (after trials
and testing (:-).
= By keeping your board square, you
can easily install this assembly inside a
Solder side view
The routing of wires is "relatively"
clean, and closely follows the original
This type of phenol circuit is
"inexpensive" (about 0.50Euro ), but
the phenol tends to be sensitive to
moisture, which could change the
frequency. A layer of acrylic varnish will
be applied later (I want to make sure
everything works as planned, before!),
to isolate / waterproof everything.
Assembly before tests
At glance, it would almost be saleable
A rapid assessment of costs shows less
than $ 6.00 of total cost.
The main part of planning of this
project is offered here.
Do not make a race out of it !
This project can be achieved in a rainy
afternoon, and done carefully, can last
Parts that require attention in the long
run, are all “mechanical moving parts”
such as the switch, the alligator clips
and the 9V clip.
Provide an easy means of replacement.
4_ A very simple zapper : RESULTS
With a supply of 8V, the peak voltage is 8V too,
which is normal (no load) with a 555 CMOS
With a 9V battery, we will get 9V peak
Note the large expected offset of 2.3V
Note: The measured frequency is 30.27 kHz with
the values shown. With a 20% capacitor and a 5%
resistance, don’t count on so much luck.
Load: 2 copper tubes with kitchen paper damp in
salty water hold in my hands.
Under load, the output signal is halved, indicating
an optimal transfer of energy. Dr. Clark knew what
she was doing, since the internal resistance (R2 =
1k) equals the load resistance (me).
LED lights better than I expected without load,
and gives a significant change when zapper is
properly connected at the output. GOOD!
For the record, here are the
results obtained with the original
Notice the 0.25V offset on the
original zapper, while the
amplitude is near: 6.20Vcac for
Clark_Original (without protection
diode) 5.7Vcac on our zapper,
with diode protection.
IMPORTANT NOTE: This page
contains directions to make a
zapper build with all the
recommendation of Dr. Hulda
Clark. Unable to check /
oversee its construction and /
or its use, please understand
that you do so entirely at your
own risk and responsibility.
Some experience in electronics is
This device has been assembled
and tested, without any
We can not, in case of
malfunction, help you
troubleshoot YOUR zapper, but ...
We will be happy to hear from
you, your experience and your
comments on this page.
A newborn must have a name.
We will call-it ZWS02
= Implement all the recommendations of Dr. Clark
= 12 components at low price: under $ 6.00 total, expected, for the builder of this zapper
= Can work with a supply from 7 to 15Vdc.
= Protected against reverse voltage of the input
= On / Off switch, indicator light.
= Stand by current: 100uA (0.1mA - lower consumption in the world, for any zapper !!!)
The original zapper of Dr. Clark consumed 40 times more, in stand by mode!
= Alkaline Battery : unnecessary (too expensive). SHD battery (2 for $ 1.00) is good enough.
= Equivalent performance with the original Dr. Clark zapper
= Gives a clear indication of "zapper well connected" (Rare and important)
This design seems to be a nice
milestone in the zapper’s field,
based on Dr. Hulda Clark
recommendations. Enjoy this
“free of any constrain” design.
However, if you do a
commercial version out of this
zapper, I would appreciate
if you make a nice reference to
“your inspiration" :
Thank you for your kind
intellectual honesty. Your
customers will appreciate it
Certain Internet sites associate zapper and serious illness.
It is not our role to make such assertions.
Illness does not interest us.
We leave it to the experts of the unhealthy states.
We are only interested to feel better, which is highly subjective, and to get rid of as much “invaders” who drain our resources, as possible.
These invaders, who live at our expense, we name them under the generic name of “parasites”.
We experience the influence of the zapper effect
on these parasites, on a hypothetical and empirical basis, which have nothing to do with medical or scientific rules.
Legal disclaimer :
We do not prescribe, diagnose, or make any medical claim or advices.
The principles, assumptions or theories exposed here have no medical or scientific value officially recognized.
Please note that Dr Clark’s books or devices have not been evaluated by Health Canada (Canada) or Food and Drugs Administration (USA), and then, have not received any guarantee on their effectiveness or their safety.
Zappers can only be sold or used as experimental devices for educational research. They are not intended for use in the cure, treatment, prevention, diagnostic of any disease.
If illness is an issue, please consult a licensed health professional before attempting any self health program.
By using this information without the approval of a licensed health professional, you are prescribing for yourself, as permitted by law, and you take full responsibility for the results.
These results may vary depending on individuals
Interesting note : This zapper
is a much better choice, for its
specs and SAFETY, compared
in the test bench, which sells
for almost $200 on eBay (and
at that price, it even not
provide you an ON-OFF switch
Applied Electronic to Well-Being