Introduction: Variable Cheap High Voltage Power Supply

Picture of Variable Cheap High Voltage Power Supply

Build a regulated high voltage power supply for capacitor charging or another high voltage application. This project can cost less than $15 and you will be able to obtain upwards of 1000V and be able to adjust the output from 0-1000V+.

This instructable is for those with excellent electronic safety knowledge.

This device can easily KILL you as well as explode. BE VERY RESPONSIBLE AND BE VERY VERY CAREFUL NOT TO DIE, it is usually a bad thing.

This device is notsafe, if you think it is safe you're wrong :)
(I got mine off Ebay for a good deal) Thank you


General Voltage Multiplier:

-Stranded Wire(18-22gauge)
-Disposable cameras(for free capacitors, which you can obtain by asking a local photo store, such as in Walmart,6 for 1000V output)(You can also buy capacitors online)(>330V, >120uF the more capacitance the capacitors have the more efficient your supply will be)
-1000V 6A Diodes(6 for 1000V output)(you can use diodes rated at 400V 6A and up if disired)
-Wall Plug
-120VAC 16A SPST Switch

Regulator Parts:

-9-14VDC 1A plug in Transformer (you can just use a 9V Battery if a transformer is not on hand)
-Two small protoboards (One is optional for the voltage multiplier)
-LM7805 Voltage Regulator
-LM393 Comparator(or LM1393 for better performance)
-12VDC 30A Relay
-8 pin DIP IC Socket
-Transistor(3904 or upwards)
-1 diode (100V 1A)(IN4001)
-2 small capacitors (.01-.1uF)(can be obtained from disposale cameras)(optional)
-2 LED Indicator lights(optional, can be obtained from disposale cameras)
-See step 2 for resistor details

-Most of the parts listed can be obtained at or
-I got my protoboards at
-The Relay at for only $1.25, works great
-I got the transformer for cheap at harbor freight.

These places are just where the cheapest parts are that I've found so far. It may be more economical to buy the parts at one place due to shipping costs.




Step 1: Voltage Multiplier

Picture of Voltage Multiplier

The Voltage Multiplier can be made separately without the regulator if necessary. The first step is to put the capacitors together. Use larger capacitance to maximize the voltage reached and regulator functioning. If you want to mount yours on a protoboard just slide in and solder you capacitors in place. If a protoboard is not desired, simply tape or glue them together. Solder your diodes on according to the schematic below.

It is important that you test your voltage multiplier before you hook it up to your regulator.

Step 2: Voltage Regulator

Picture of Voltage Regulator

The Voltage Regulator will take a bit more time than the multiplier but once done it will be well worth it. Test the basic schematic on a breadboard before you make a permanent arrangement if you find it necessary. After you have tested it just solder all of the components in place following the schematic and picture.

Resistor values:

Values for 6 Capacitor/Diode Multipliers:
VR1-10K Variable Resistor

If you wish to have a higher or lower output voltage the resistances will need to be different. Or if you have different valued resistors for RA or RB.
Use the following equations to figure out your values.

Min resistance=(HV*HV)/(total resistor power rating in Watts)


Where HV is the output voltage of the multiplier
Resistors need to be rated for HV

Step 3: Putting It All Together

Picture of Putting It All Together

Put it in a container or box and just finish it all up.

-NEVER TOUCH THE OUTPUT LEADS(the capacitors can still be charged even after shut-off, and yes it can and Will kill you)
-NEVER SHORT THE MULTIPLIER OUTPUT LEADS(The capacitors will explode!!)

I take no responsibility for you shocking, hurting, or otherwise acting stupid around this device. BE SMART!!

Oh, and have fun :)


leaualorin (author)2011-06-12

This has to be the funniest thing I ever read :
"AND BE VERY VERY CAREFUL NOT TO DIE, it is usually a bad thing."
But yes, very good info in this instructable!

quake2u (author)leaualorin2015-12-15

Yeah hold my beer and watch this.

ightmeaki (author)2015-11-20

What is the amperage on this?

ightmeaki (author)ightmeaki2015-11-20

I need it to do at least 12 amps. How do I do it?

leviterande (author)2013-08-02

Hi, does we need fast diodes for this? I saw you use transistor that usually do in the kHz range so ..

skotagond (author)2012-06-25

i want to do a variable power suppy ranging 0-50v using the mains and also a transformer.... plz help me about my work !!

padmanabhapsimha (author)2011-05-17

this is certainly not dangerous. this is quite a good design. but i don't think that voltage multipliers are as efficient as switch mode power supplies or flyback drivers which are capable of giving out more power.

aweis (author)2011-05-15

would i be able to change the power from instead of a wall outlet a 70 volt generator, to make at least 500v. i want to make a hand crank tesla coil and i need a high voltage power supply, is there any way to size this down for less power input?

burningsuntech (author)2008-05-04

Nice job. I like the 'lets look inside' idea with the clear plastic. An improvement to consider would be to use the high voltage feedthru from a microwave oven magnetron tube as your output terminal. It is rated at 5Kv and would dress up the box a bit. Could you use an external 12VDC 1.5Amp power supply and eliminate the internal 9-14 Volt supply? raving apache

Yes any external supply within the 9-14V range would work, you could even use a 9V battery if you want.

so what you saying is that this will work with any voltage , even form batteries?
so technicaly this means that if i made this, but only in 2 stages, this would then multiply the voltage twice correct? say from 8 v dc to 16v dc
or would i need to make more stages but use weaker capasitors r the same, im relay in a pickle right now i cant sem to find any voltage multiplier instructions on the web for doubling voltage from 4 to 12 or 6 to 12

ste5442 (author)rwilsford072009-02-03

A battery would be best - especially if you dont know how your bench power supply -Ve lead is connected internally! You could end up with some interesting results!
I would recommend sticking with either a floating supply like a battery or the authors existing circuit for the safest results ;-)

PCBPolice Electronics Forum - we need some users....please!....don't make me beg!

Kante Tech (author)2010-09-04

you build a filp cover for the capacitor leads so no one will accidently touch it

pyrosparker (author)2010-07-22

is 1000v enough to make an arc?

Jimmy Proton (author)pyrosparker2010-08-08

1kV=1mm arc

tristantech (author)2010-03-25

We do not care about commenting negatively. This is a serious safety concern. This is a bad design and if someone were foolish enough to make this, something bad could happen.

garrys newman (author)2010-03-07

i see you use 6A diodes  but your circuit if feeded whit 1A max (depend on the transfo)  i imagin that 1A diode should be on the limit ???

the rating you said is what you use   but is it the minimum requirement?

surgeon (author)2009-08-19

This looks like a dangerous circuit. The HV is somehow couple to the variable resistor. This is potentially dangerously. This is certainly not a good way to create a HV supply.

hydra rov (author)surgeon2010-01-26

I agree this design should not be allowed to be published on this site its highly dangerous and is a safety hazard, i bet the designer is not even HV qualified,l it breaches a multitude of electrical regulations both in the EU and USA/Canada im sure the IET and IEEE would not be happy..

Re-design (author)2009-09-30

Where's your isolation transformer on the hv input side.

rwilsford07 (author)Re-design2009-09-30

Proper and safe design would implement an isolation transformer, this however does not.

Mudbud (author)2009-09-12

uhm I really like the cool power supply you made....but how is the 10k variable resistor conected to the HV. Is that varistor connected to the HV? If it is I dont know how it doesnt explode from the HV.

Electronics111 (author)2009-08-21

I would like capacitors please. :)

Private message me with your capacitor requirements and we can work something out.

duckythescientist (author)2009-05-28

I believe that your power supply is poorly designed. The wall transformer has a too low of a ratio for creating very high of a voltage, and it has too high of a K (I think is the abbreviation for coupling) to operate resonantly. Also your Cockroft-Walton multiplier's capacitors are too big for the current and frequency that your xfmr operates at. I would like to see proof of successful operation and be proven wrong. has a wonderful CW calculator that you might want to look into. As I said, I'd be even happier if you prove me wrong and show that your setup is a good design.

kgbkiller (author)2009-05-17

Hey. I have a question: can u give more details about power supply plz. For example where can i buy 9-14VDC transformer? Thank you.

sabre (author)2008-10-01

where did you find your diodes?

rwilsford07 (author)sabre2008-10-01

online at

Jonesy939 (author)rwilsford072009-05-06

what is the power output of your supply? how many amps can you pull out of it?

sabre (author)rwilsford072008-10-01


rwilsford07 (author)sabre2008-10-01


sabre (author)rwilsford072008-10-01


onlyonething (author)2009-04-18

nice job 5 stars and fav'd

justinpruss (author)2009-02-04

Okay, hopefully this is the last question I'll have, but would the LED (LED1)between RL3 and the diode change how it works if it isn't working -- cause its not lighting up and LED2 is. I presume it is a bad LED (or backwards XD).

justinpruss (author)justinpruss2009-02-04

okay, LED1 doesn't light up cause its getting 0.1V right now. The variable resistor doesn't change anything, the relay kicks twice and then stays on. LED2 lights up and the LM7805 is working like it should. Is the LM393 broken? or is it possibly something else. I get 985V and nothing less.

rwilsford07 (author)justinpruss2009-02-05

Recheck your circuit very carefully and if everything is like it should be, replace the LM393, it sounds like it is the problem.

LastActionTubby (author)2008-08-27

Fine Instructable, but I have to comment on a couple of things:

1. Your statement, "This instructable is for those with intermediate electronic and electronic safety knowledge, but if you really what to build this and have little experience, feel free to ask questions."

No. This is for those well-versed in mains-level and high-voltage systems. If you really want to build this and have little experience, find something else you really want to build: you will very likely kill youself.

2. Wall plug + No transformer + Connecting "Neutral" to Earth Ground = Tragedy.
a. If you are lucky, you'll plug this into a GFCI-protected socket, which will promptly trip since half the return current is flowing into Earth Ground instead of Neutral.
b. If you're not lucky, the oulet is wired incorrectly, and you're shorting the Live side to Earth Ground, resulting in a minor detonation of the relay contacts and hopefully a blown fuse.
c. If you are even less lucky (which in HV work is the usual case), the socket's "Earth Ground" isn't actually connected to anything. But now your "GND" sure is - one of either Live or Neutral. "Bah, sure it's HV, but GND's GND, right?" may be your famous last words.

Bottom line: Put a 1:1 transformer (or two back-to-back 1:N<->N:1 xformers) between the socket and the rest of the circuit to make it a little less deadly and a lot more house-wiring friendly.

ste5442 (author)LastActionTubby2009-02-03

I agree that its not an instructable for those new to electronics (although the author makes repeated warnings about safety) and I agree that an isolation transformer is a good idea but I do disagree with your other points.

*The neutral is NOT connected to Earth - it is connected to the circuit 'common' so the circuit looks fine and there are no earth leakage issues to trip a breaker.
*Your other comments are answered with the above comment!

Really, if the author connected the neutral to earth I suspect he would notice right? ;-)

The circuit, although lacking some output decoupling on the reg and a decoupling cap on the opamp, is a nice, elegant design.

PCBPolice Electronics Forum - we need some users....please!....don't make me beg!

Yes an isolation transformer should always be a must when playing around with the mains.

ubr.bzkr (author)2008-10-06

I was wondering, could this be modified to have a max output of around 5000 volts. I have a book "electronic gadgets for the evil genius" that tells you how to make a power supply that is capable of producing 5000 volts, but it is more complicated and much more expensive than this 1000 volt power supply. if it is possible to get an output of 5000 volts from a camera capacitor bank then I would much appreciate it if you could instruct me on how to do this.

rwilsford07 (author)ubr.bzkr2008-10-06

Continue the voltage multiplier...More capacitors, more diodes, more insulation, and make sure it is grounded at the negative output and has a fuse to protect it all.

ste5442 (author)rwilsford072009-02-03

Or maybe try to find a neon sign power supply online (maybe ebay?) - you can get them in varying voltages from say 5kV up to 25kV or so. These things certainly are dangerous though since they can offer up to 25mA at these voltages....ouch!

PCBPolice Electronics Forum - we need some users....please!....don't make me beg!

justinpruss (author)2009-02-03

Hello again, I was testing the thing and it generated 1000v just like it should, but the relay buzzed twice ans stopped buzzing, and the variable resistor doesn't seem to change the voltage at all. This happens each time i turn it on. I have rechecked the variable resistor and it is correctly connected, my question is what do you think could be the problem? I was also wondering if using 4 pins of the relay would do this, because that is all i have connected. My relay has 5 pins - two for the coil, two for each side of the switch thing and then one for the switch thing. my problem with connecting both the 87a and 87 is that it make the one side of the AC input grounded and shorts. :( sorry for the long-winded post.

rwilsford07 (author)justinpruss2009-02-03

The 87a should be connected to the device where the ground symbol on the schematic is and the 87 pin should be unconnected. Firstly do not connect the third prong on your wall plug to the schematics ground, but the output ground and the low voltage input (from your transformer) ground need to be connected. Did you use a diode between the coil ends of the relay? The third prong should not short the AC, but I don't use it so see if it works without it.

justinpruss (author)rwilsford072009-02-03

oh i see, so the ground from the multiplier isn't connected to the third prong? I do have the diode at the relay, and the ground not being there should fix that problem. Other than that it works beautifully.

justinpruss (author)justinpruss2009-02-03

okay, just a thought -- is the capacitor for the lm7805 necessary because i don't have one there, and your schematic doesn't show one.

ste5442 (author)justinpruss2009-02-03

I think that is a small typo, the output capacitor on the 7805 should be there.
There should also be some decoupling on the +Ve pin of the opamp - especially since there are HV and potentially high current transients nearby.

PCBPolice Electronics Forum - we need some users....please!....don't make me beg!

illdoyourdrugs (author)2008-08-26

I am a def noob at all this but would love to understand how to build this. Any body have some suggestions on where i can learn this stuff better and understand the diagrams and holes in the PCB. i dont know where to place them or what. i know the symbols. Could i buy one from you?

Pie Ninja (author)illdoyourdrugs2008-12-17

You could take a course in electronics at university. Or, alternatively, you can buy books on circuitry and whatnot at most bookstores or borrow them from a library.

ste5442 (author)Pie Ninja2009-02-03

Or buy 'The Art Of Electronics' and read it front to back.
This is probably not the instructable for you if you are a total newbie - you are quite likely to break yourself :-)

PCBPolice Electronics Forum - we need some users....please!....don't make me beg!

About This Instructable




Bio: I make stuff sometimes. Now that I have a job and family less than I could, but i love spending time with them so it ... More »
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