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Build a Variable High Voltage Power Supplyby burningsuntech on October 27, 2007

Table of Contents

Build a Variable High Voltage Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Intro:   Build a Variable High Voltage Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Step 1:   Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Step 2:   Gather the parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Step 3:   Lay out the chassis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Step 4:   Wire the low voltage side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Step 5:   Complete the build . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Step 6:   Power UP and Test it . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Step 7:   Safety Rules, and Disclaimer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Related Instructables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

http://www.instructables.com/id/Build-a-Variable-High-Voltage-Power-Supply/

Author:burningsuntechBorn in New Mexico on or about the time of the crashed alien ship near Roswell(changeling maybe?), I am a direct decendent of the Apache warriorGeronimo. I like bodybuilding, computers and high powered devices. Wow! An indian with an attitude.

Intro:  Build a Variable High Voltage Power SupplyI needed a variable 0 to 50KV high voltage power supply for my high voltage experiments that wouldn't break the bank, so I built my own.

With just a few parts from old microwave ovens, TV sets, and an oil burner, you can build an affordable instrument for whatever you wish to snap,crackle, or pop!

The key component is the voltage multiplier, which I covered in the High Voltage Multiplier instructable. Build it first, then drop it into this project for a variable output.

Image Notes1. Input Voltage Adjustment which varies the output voltage from 0 to 50 Kv in(100) 500volt steps.2. This is the feedthru insulator and the stud in the middle is the output.3. The case is an old Texas Instruments TI99 computer box. Any metal casewill do.4. HV ON pushbutton and indicator.5. Power Switch and READY indicator.6. Removable top cover for easy maintenance

Image Notes1. This test was at 25,000 Volts or 50 percent setting on my supply. The brightblue white spark is evidence of high current and lots of ultraviolet rays.

Step 1: Theory of OperationThe diagram shows the supply in the de-energized condition and the case closed.

Mains voltage is applied to the power supply thru a 120 VAC Panel connector. With the case closed, current passes through a 5 Amp fuse, F1 and through the casesafety switch, S1 causing the Ready indicator, I1 to light when the power switch S2 is placed in the ON position to energize the supply.

At this time, the power supply is NOT ON but in a state of readiness to enegize the high voltage stage.

When pushbutton S3 is pressed, relay K1 energizes and remains energized after S3 is released.

Current passes through Variac, VT1 which adjusts the input voltage to the OBT. The OBT steps up the input voltage to a maximum of 6,000 VAC. The output of the OBTis fed to the high voltage multiplier, HVM where it is multiplied to 51,000 VDC output.

To de-energize the supply, place S2 in the OFF position. K1 will de-energize and remove power from the OBT and HVM and all indicators will extinguish.

The case safety switch and the power contactor are not necessary for this supply to work. I thought the ability to power on and off by using a pushbutton was cool. Thatsall. The second schematic shows them removed.

http://www.instructables.com/id/Build-a-Variable-High-Voltage-Power-Supply/

Image Notes1. 0 to 120 VAC variable output.2. 0 to 6,000 VAC3. 0 to 51,000 VDC output.

Step 2: Gather the partsAll the parts with the exception of the variac used for voltage control came from my junk collection or Ebay. Here's the list:

CHASSIS - Texas Instruments TI99 Computer case. Any metal box will do as long as there is enough room for the parts. An electrical box will do just fine. The computercase had a switch, an AC plug adaptor, and a removable lid so it was perfect.

F1 - 5 Amp fuse with holder (Radio Shack).

HVM - HV Multiplier - This is a build it yourself part made up of (6) 12KV High Voltage Diodes and (6) 470 picofarad 20KV High Voltage ceramic doorknob capacitors.You can buy all the parts on Ebay. I have already posted an instructable on this. Just search for High Voltage Multiplier.

I1 - READY Indicator - GREEN 120 volt Neon lamp (Radio Shack). An old 120 volt Neon indicator from a microwave oven is what I used here.

I2 - HV ON Indicator - RED 120 volt Neon lamp (Radio Shack).

K1 - Contactor - 120VAC 10 Amp DPST Relay with a 120VAC coil.

OBT - Oil Burner Transformer salvaged from an old oil burner from a mobile home rated at 120VAC @ 2.25 Amps on the input and 6Kv 20Ma on the output. The singlepole type was used here. This can be purchased from a burner service company for about $65.00

S1 - SPST N.O. Cherry Microswitch for case safety.S2 - DPST Toggle or rocker switch for power on.S3 - SPST N.O. 120VAC Pushbutton switch.

VT1 - A variac was purchased for $60 from an electrical supply house. Any dimmer that can handle inductive loads up to 5 amps will work. The variac can control 2.5amps. Just enough for the OBT.

MISC - You will need some wire lugs and various colors of wire scavenged from power cords for the internal wiring.

Image Notes1. Case Safety Switch used to cut power when the case is opened.2. AC Power Adaptor also has a fuse holder built in. If yours doesn't, you will need to add a 5 amp fuse with a holder to the list3. Power Contactor or Relay for controlling the HV Circuit.4. Variac for input voltage control.

http://www.instructables.com/id/Build-a-Variable-High-Voltage-Power-Supply/

5. Oil Burner Transformer produces 6000 volts AC at 20 Milliamps for the multiplier on right6. Multiplier for raising the 6000 volts to 50,000 volts at the same current.7. High Voltage Start switch with indicator.8. Power switch and indicator9. Added back panel

Step 3: Lay out the chassisIf your box has stuff in it, gut it. Take everything out of it except essential parts. I kept the power switch and the AC Adaptor. Everything else, GONE!

If your box has HANDSIZED holes in it, patch em. You don't want little ones (or a nosey neighbor) sticking their paw in the box with power on. Mine needed a cover forthe back and a new face plate made of sheet aluminum. It would have cost me less to just use an electrical box instead.

Next, layout all the parts in the approximate locations shown giving yourself plenty of room for wiring. Space is essential in this project because we want to limit thepossibility of arcing between high voltage components.

Drill holes where needed for mounting the parts and secure your parts using whatever hardware you have for working with sheet metal.

Image Notes1. Case Safety Switch used to cut power when the case is opened.2. AC Power Adaptor also has a fuse holder built in. If yours doesn't, you will need to add a 5 amp fuse with a holder to the list3. Power Contactor or Relay for controlling the HV Circuit.4. Variac for input voltage control.5. Oil Burner Transformer produces 6000 volts AC at 20 Milliamps for the multiplier on right6. Multiplier for raising the 6000 volts to 50,000 volts at the same current.7. High Voltage Start switch with indicator.8. Power switch and indicator9. Added back panel

Step 4: Wire the low voltage sideDecide if you are going to include a power contactor and case safety switch. If so, use the first schematic. If not, then use the second schematic.

Wire the supply starting with the AC connector, fuse holder, switches, variac and power contactor.

Test each stage of your build to make sure your wiring is correct.

Next wire up the OBT and test the range of the variac.

To test the output of the OBT, hold a GROUNDED screwdriver near the OBT output terminal.

If you see an arc, good. Power off the supply and disconnect it from Mains and move to the next step.

http://www.instructables.com/id/Build-a-Variable-High-Voltage-Power-Supply/

Image Notes1. 0 to 120 VAC variable output.2. 0 to 6,000 VAC3. 0 to 51,000 VDC output.

Step 5: Complete the buildDepending on how you built your multiplier, you need to mount it to the chassis so it doesn't move around. In my case, I made a pair of homemade U shaped woodenmounts and glued the multiplier to the mounts using contact cement.

When dry, mount the multiplier in the chassis and wire it to the OBT and ground.

For the output, I passed the 50KV lead through the chassis using a 2 inch large rubber stopper as a grommet and some corona dope to prevent arcing. This worked until Ipassed the 35KV mark and then it arced over.

So I bought a screw on PVC plug and passed a 2 inch brass screw through the center, then filled it with 30 minute epoxy and let it cure.

I secured the feed through to the chassis with a piece of threaded PVC pipe to match. I then cut my 50KV lead to length and soldered it to the screw head on the back ofmy feed through.

I coated the whole assembly with corona dope, let it dry, and tried again. This time I succeeded and got to the 50KV mark at 100 percent without any arcing

Image Notes1. Input Voltage Adjustment which varies the output voltage from 0 to 50 Kv in(100) 500volt steps.2. This is the feedthru insulator and the stud in the middle is the output.3. The case is an old Texas Instruments TI99 computer box. Any metal casewill do.4. HV ON pushbutton and indicator.5. Power Switch and READY indicator.6. Removable top cover for easy maintenance

Image Notes1. This test was at 25,000 Volts or 50 percent setting on my supply. The brightblue white spark is evidence of high current and lots of ultraviolet rays.

http://www.instructables.com/id/Build-a-Variable-High-Voltage-Power-Supply/

Step 6: Power UP and Test it*** WARNING ***THESE NEXT STEPS ARE DANGEROUS.

Connect the power to the supply and turn on the main power switch. The "Ready" Indicator should light.

Set the voltage to 50 percent and press the HV ON pushbutton.

The HV ON Indicator will light and you will hear a slight hissing sound. This is okay. If you hear any snaps or arcing, determine where the problem is, shut off the supply,and dope the area. When it dries, test again.

With a grounded screw driver, bring the tip of the screw driver in close proximity to the output stud and watch for sparks.

*** WARNING ***DO NOT TOUCH THE OUTPUT STUD WITH THE SCREWDRIVER. PERMANENT DAMAGE WILL RESULT.

If you are confident in your building skills, or hungry for sparks, SLOWLY ramp up the voltage to 100 percent and test again with the screwdriver.

Success will be indicated by the 2 inch long spark that you get from the supply.

*** WARNING ***DO NOT ATTEMPT TO MEASURE THE OUTPUT OF THIS DEVICE WITHOUT SPECIAL TEST EQUIPMENT OR THE PROPER SAFETY EQUIPMENT.

*** DANGER DANGER DANGER DANGER DANGER DANGER ***

THE CURRENT PRODUCED BY THIS SUPPLY ALONG WITH THE HIGH VOLTAGE MAKES THIS DEVICE DANGEROUSLY LETHAL! DO NOT TOUCH THE HIGHVOLTAGE STUD DURING OPERATION. THIS THING WILL KILL YOU! GROUND THE STUD AFTER EACH SHUTDOWN TO DRAIN ANY REMAINING POTENTIAL.

Image Notes1. This test was at 25,000 Volts or 50 percent setting on my supply. The brightblue white spark is evidence of high current and lots of ultraviolet rays.

Image Notes1. Input Voltage Adjustment which varies the output voltage from 0 to 50 Kv in(100) 500volt steps.2. This is the feedthru insulator and the stud in the middle is the output.3. The case is an old Texas Instruments TI99 computer box. Any metal casewill do.4. HV ON pushbutton and indicator.5. Power Switch and READY indicator.6. Removable top cover for easy maintenance

Step 7: Safety Rules, and DisclaimerSAFETY FIRST!

ALWAYS wear rubber safety gloves and stand on a rubber safety mat when operating this supply.

ALWAYS wear protective goggles when power is on. Especially if you plan to power a laser with this unit.

NEVER touch anything or device that is connected to the supply while it is in operation without adequate protection.

NEVER defeat the safety switch on the case or operate this supply with the lid removed.

DISCONNECT the supply from power before opening or working on it.

FOCUS your attention on what you are doing with this device. Eliminate any distractions or annoyances in the area where you use this device.

DO NOT ALLOW others to operate or work in the same area of this device without adequate supervision or safety training.

REMEMBER, Smokey says, only YOU can prevent People Fires!

*** DISCLAIMER ***You, the builder and user, bear the responsibility for your own safety in building, testing, and using this supply. By building this device, you acknowledge the risks involved

http://www.instructables.com/id/Build-a-Variable-High-Voltage-Power-Supply/

in it's operation and accept those risks as a result. I will in no way be held responsible for your actions, including your death by this instrument and you accept theseterms by building and using this device.

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Comments

50 comments Add Comment view all 100 comments

 Moo_cow says:  Jan 10, 2011. 9:54 AM  REPLYIf I were to take out the multiplier, would if work for 0-6000 volts?Wanting to use this for part of my science fair but I do not need to go over 6000 volts.

 burningsuntech says:  Jan 11, 2011. 7:19 AM  REPLYMoo_cow

If you only want 0 to 6000 volts AC, then the answer is yes.

If you need 0 to 6000 volts DC, then you must add a single 12KV Diode to the output of the transformer.

Good Luck in the science fair.

RA

 ewpwrqlty says:  Dec 20, 2010. 5:55 PM  REPLYI only need a 100-700 VAC variable supply. Can I modify your design to achieve this goal?

 burningsuntech says:  Dec 21, 2010. 5:55 AM  REPLYPossibly.

without knowing details like how much current you want the device to provide and at what voltages, I wont be able to help.

More info is needed besides "can I modify your design to achieve this goal?"

RA

http://www.instructables.com/id/Build-a-Variable-High-Voltage-Power-Supply/

 ewpwrqlty says:  Dec 21, 2010. 8:01 AM  REPLYThanks for your quick response.

The device does not need to provide any current. I only need to provide variable voltage potentials between 100-700 VAC. I am attempting to createa voltage calibration set for my BMI 8800 power disturbance analyzers.

The required voltage (Vrms) calibration levels are:

1. 02. 7.6-8.43. 30.2-33.44. 75.5-83.55. 150-1706. 200-2257. 300-3358. 604-670

I am using a 0-140VAC Variac to produce the first four levels.

I tried using a hipot tester to produce the last four levels and was successful up to level 8. The hipot unit that I own is a Hiptronics HD5 0-5KV at 5mA.The impedance of the BMI voltage input channels during calibration is 1.01 Megga Ohm. At approximately 500 VAC the leakage current light wasglowing and the unit was vibrating and ready to fail on leakage. My Hipot tester would need to have at least a 20 mA output capability in order tocomplete the calibration series

 burningsuntech says:  Dec 31, 2010. 2:55 PM  REPLYOn second thought... You would need a 0 to 800 volt Transformer and use the variac to supply the variable voltage to it.

With a vernier dial on the Variac, you would have a calibrated settings range. If you need finer settings, say in millivolts, you would need a twenty-five turn vernier instead of a ten turn vernier.

Hope this helps.RA

 burningsuntech says:  Dec 28, 2010. 2:21 PM  REPLYewpwrqltyYou could use a switch to select one of two ranges. The first range would be what is supplied by the Variac. The second range would be additionof another step-up transformer connected to the output of the variac.

With a Vernier knob attached to the variac and a volt meter, of course, you could tune the output of the step-up transformer to the appropriateranges based on where the vernier is set.

That would give you your ranges and the desired voltages though it might be a bit cumbersome.

One other possibility would be to calculate the output of a transformer given the input voltage and the number of turns on the output. If you areadventurous enough, you could design and wind your own transformer for the desired output ranges beyond the output of the variac and use aselector switch to select the output tap for the given range you desire.

It takes some doing and a bit of knowledge of transformers but it can be done.

Lastly, you could also have a special transformer built for this purpose which would give you all the ranges based upon which tap you choose.

There are other methods but I do not build devices for people nor do I have the time for these projects as i am currently busy running a business.

Good luck. i hope this helps.RA

 ewpwrqlty says:  Dec 11, 2010. 8:51 AM  REPLYI need to build a variable AC power source from 0-700 Vrms for calibrating my BMI 8800 power disturbance analyzers. There are 8 voltage ranges that thepower source needs to provide: 0 Vrms, 7.6-8.4 Vrms, 15.1-16.7Vrms, 30.2-33.4 Vrms, 75.5-83.5 Vrms, 150-170 Vrms, 200-225 Vrms, 300-335 Vrms, and604-670 Vrms.

Do you have any suggestions? Any help would be greatly appreciated.

 CharlesBarret says:  Jun 21, 2010. 9:13 PM  REPLYHi, i think that your source cannot supply that much current (20milis) because that depends on your load resistance.. mmm how do you know you can holdthat much current in your design? thx..

 burningsuntech says:  Jun 23, 2010. 4:48 PM  REPLYCharlesBarret Technically true. The problem is with the type of transformer used in this supply. The specs of the OBT state that it will supply .02 Amps at6000 volts. This transformer does have a load in the form of an air gap approximately 1 cm in length. With the resistivity of air equal to anywhere from10^8 to 10^9 ohms per meter then resistivity of a one cm gap is 10^6 to 10^7 ohms. This assumes that the air has not ionized. (which is the point of anOBT anyway). After ionization of the air, the conductivity increases dramatically to the point of a near short circuit. To prevent that from becoming a deadshort, there are current limiting windings built into the transformer to limit maximum draw to 20 ma. So, the maximum draw from this device is limited to20 ma. But if there is a resistive load placed on this supply, it will be somewhat less based on Ohms law. Hope that explains the specification. Thanks forthe question. RA

http://www.instructables.com/id/Build-a-Variable-High-Voltage-Power-Supply/

 silicacat6 says:  Jun 21, 2010. 4:33 PM  REPLYWould you please assemble and sell me a high voltage DC power source? Input either 24 V DC or 220VAC, your choice. (I would prefer to use 24V DCinput). The max voltage required ~900V and max current 5A. Name your price, and have a guess at when you could deliver. Thanks derikh6@yahoo.com

 skeric17 says:  May 28, 2010. 6:56 PM  REPLYhello i was wondering if u could please give me a few pointer on making a 0-12v variable power supply i dont know where to begin thanks for ur time andhelp=]

 burningsuntech says:  Jun 10, 2010. 3:00 PM  REPLYI can point you in the direction of either the internet or Radio Shack engineering booklets which would have circuits that would work for you. Do a GoogleSearch for 12volt power supply schematic. There is tons of them out there. Good luck with your project. RA

 simondodd says:  Feb 16, 2010. 6:47 AM  REPLYGreat job!! I am thinking of building this with myNST and using it for my Tesla Coil.  However all the plans I have seen for Tesla coils require both the hot andcold output from the NST. Would this be the HV output and the case/ground or would I have to wire it up slightly differently?

Thanks in advance

Simon

 ElectricUmbrella says:  Oct 24, 2009. 2:38 PM  REPLYHi, very nice idea, five stars!I don't have an six KV Oil Burner Transformer, but I do have a five KV Neon Sign Transformer. Would that work just as well?

 burningsuntech says:  Oct 27, 2009. 8:44 AM  REPLYElectricUmbrellaYes it will.  In fact even AC (mains) passed thru a standard transformer (ie 120VAC in and 120VAC out) will give you a high voltage based on the formulain the multiplier design.  Thanks for the 5 STARs.  enjoy the build.

*** Do you have technical questions on electronics, computers, anything except plumbing, and house electrical?  Burningsuntech may have theanswers.  Just email your questions to: ravingapache@gmail.com .  We will let you know. ***

 PureAwesomeness says:  Dec 31, 2009. 3:39 PM  REPLY Hey, it's okay, I got the parts in time and it turned out fine!

 drbill says:  Dec 29, 2009. 10:43 AM  REPLYAaaaaahhh! I Like Electricity !

 BobLew says:  Dec 19, 2009. 9:40 AM  REPLYwhat should i do with the other pins?sometimes spark occured between them.especialy some closest pins with ground pin.one of pin closest is also draws purple spray, but never spark

 PureAwesomeness says:  Nov 27, 2009. 6:51 PM  REPLYHELP!

Okay, I'm doing a science project in 8th grade involving electrohydrodynamic thrusters, and I need to know how much all of this costs.  I need this stuff in like3 days or less.  Assuming I can get a crappy TV that still has a working screen from Good Will, what will be the cost of everything else?  Also, what are theRadioShack ID numbers for all of the stuff that you say I can get from RadioShack?  I could probably get the rest from Amazon, which ships in one or twodays.  For everything else, if you can, could you please give me links to the products?  I'm sorry if I'm asking a lot of you, but I'm desperate, and I'm awful atfinding the right electric parts via the internet.  Can you help me?

Thanks, PureAwesomeness

 burningsuntech says:  Dec 6, 2009. 7:08 AM  REPLYPureAwesomeness

Sorry for the late reply.

If you waited till you only had three days to assemble this project, then you set yourself up for failure.

If you intend to do anything in science or the engineering field, you have to do your own research like everyone else.  I cannot give you any assistanceabout pricing of parts etc.  Thats your problem.  Do the work if you want the reward.  Otherwise you might consider simpler projects in the future.

RA

http://www.instructables.com/id/Build-a-Variable-High-Voltage-Power-Supply/

 thermoelectric says:  Sep 20, 2009. 5:36 AM  REPLYWhen you say Multiplier for raising the 6000 volts to 50,000 volts at the same current. How is that possible? I always thought when the voltage went upthe current went down.

 burningsuntech says:  Sep 23, 2009. 6:07 PM  REPLYthermo the source of the current is the transformer and it is rated with an output of 20ma. If the tranformer output were passed thru another tranformerwith a 6000 volt primary and a 50,000 volt secondary, then you would be correct. The stepping up of the voltage in this manner would cause the currentto step down. However, the device we are using (ie the multiplier) is comprised of capacitors that charge in parallel during one half cycle of the AC inputand discharge in series on the other half cycle. The multiplication of voltage using this device has virtually no effect on the amount of current deliveredbecause the capacitors will charge to .707 or seventy percent of the peak input voltage with very little capacitive reactance. Therefore most of the currentfrom the transformer is delivered to the output. RA

 thermoelectric says:  Sep 23, 2009. 6:38 PM  REPLYAh, Thanks, That helps. Would it be possible to get AC out of the multiplier? I know it has a DC output but sometimes that isn't too useful...

 burningsuntech says:  Sep 26, 2009. 6:00 PM  REPLYthermo

This multiplier is classed as a halfwave device. That means that is uses only one-half cycle of the AC put in.

There is a fullwave version that would be a possibility. If you take the halfwave schematic and flip it on its ground line as a mirror image, youwould get a fullwave device.

Go here for more info: http://members.tm.net/lapointe/Cockcroft_Walton.htm

WARNING *

The fullwave multiplier is a dangerous monster. Notice in the schematic that all three output poles are at high potential with respect to ground.You will need to build this device with special design considerations in mind.

BTW - I have replaced the mineral oil in the multiplier with parafin. Works quite nicely too.

Good LuckRA

 thermoelectric says:  Sep 26, 2009. 6:54 PM  REPLYOh, Wow! That sure looks dangerous! I might attempt it once I get my MOT bank running (4 MOTS with outputs in series), I can't wait to bedrawing sparks at 500mA ~8800VAC *evil grin* May I ask where you obtained your mineral oil? (I thought parafin was flammable?!?!)

 burningsuntech says:  Sep 30, 2009. 4:57 PM  REPLYThermo Did you say MOT's??? Yikes man. be Wery careful silwy wabbit. MOTS do not have current limiting windings in them andtherfore produce a HUGH amount of current. Just looking at one crosseyed can get you toasted. PLEASE! BE VERY CAREFUL! I wouldhate to lose a buddy. Raving Apache

 thermoelectric says:  Sep 30, 2009. 5:50 PM  REPLYYeah, i said MOT's. I have them current limited with a heater's heating element. I need to submerge them in oil before I even dare topump a higher current through them, I already got the output of one of the MOT's to arc to the core :-/ And they actually do havecurrent limiting shunts in them, just not very effective... I'll be careful, I would hate to lose me too.

 burningsuntech says:  Sep 30, 2009. 4:51 PM  REPLYthermo Even mineral oil is flammable if you get it hot enough. I changed to parafin because it was easier to obtain and contain thanmineral oil. It remains in its solid state as long as it doesnt get too hot, way below its ignition point. I got my mineral oil at Wal-Mart. or anydrug store will do.

 thermoelectric says:  Sep 30, 2009. 5:47 PM  REPLYYou think the drug store would be suspicous of me buying a couple of litres of mineral oil? Lol. I need that much to fill the bucket myMOT's are in...

 burningsuntech says:  Oct 5, 2009. 5:57 PM  REPLYthermo There are tons of more dangerous stuff in a drug store than mineral oil and I don't mean drugs either. An mineral oil is notdangerous. BTW - I dyed the parrafin red with a red crayon so I could detect any leaks in my pour into the container. No leaks butit looks techie, though. Cool.

 thermoelectric says:  Oct 5, 2009. 10:59 PM  REPLYCool! I'm gonna email my chemist to see if they have enough for my needs...

http://www.instructables.com/id/Build-a-Variable-High-Voltage-Power-Supply/

 Mudbud says:  Sep 12, 2009. 3:22 PM  REPLYTHATS A THIN WIRE!!! for 25kv? careful with that wire.

 burningsuntech says:  Sep 12, 2009. 7:32 PM  REPLYElectro Nerd You mean the one shown on the pic with the arc from the stud? Actually, that wire is grounded and its voltage breakdown value is irreleventbecause it is at ground potential. It happens to be 12 Ga. stranded AC wire. No if we were talking about powering from the stud, then yes, you should usea highvoltage rated wire of at least 25Kv. raving apache

 votedthewave says:  Jun 16, 2009. 12:34 AM  REPLYIs this -50kv or +50kv?

 Electronics111 says:  Aug 18, 2009. 6:00 AM  REPLY+50kv i think

 electrophysics_man says:  May 26, 2009. 7:50 AM  REPLYDoes anyone have an oscillograph of the output signal of this power supply? I would like to see what the output looks like before I build it in order to verifythat it will work for my purposes before I purchase the parts and build it.

 elphreaker says:  Apr 26, 2009. 1:10 PM  REPLYNice instructable mate , you encouraged me to set it up , I have all the AC part done at the moment and tomorrow ill get the multiplier and the box ready ;)

 ushirmaharaj says:  Dec 16, 2008. 9:56 AM  REPLYcan i use this to power a marx generator

 burningsuntech says:  Dec 27, 2008. 10:38 AM  REPLYHI Yes you can. The output is pulsating DC and should work for all HV applications drawing less than 20ma.

 ozetzioni says:  Oct 31, 2008. 11:31 AM  REPLYHey, I am building a pedal generator bike with a battery. at the end of the day i want to transfer the electricity i made of riding into a bigger battery and thenuse it for lighting equipment... anyone knows of a method to transfer the electricity from one battery to a bigger one without losing voltage or too muchenergy???

 anonomas29 says:  Oct 16, 2008. 4:17 PM  REPLYwire this up to a doorknob that u dont want people going in

 burningsuntech says:  Oct 18, 2008. 7:37 AM  REPLYanonomas29 What about DEATH don't you understand? This is no toy but a serious instrument. Do you really want to go away for life for murder? Youbetter think again! Raving Apache

 Derin says:  Oct 17, 2008. 11:20 PM  REPLYno no no!use plasmana's smallest shocker for that

 ubr.bzkr says:  Dec 4, 2008. 4:10 PM  REPLYor you can use that worlds smallest shocker to zap people for fun like I do. that was one of my favorate instructables.

 Derin says:  Dec 5, 2008. 9:56 PM  REPLYThat was what I was talking about.

 ubr.bzkr says:  Dec 6, 2008. 7:12 PM  REPLYyeah. did you build one?if not you should, its real fun to use on/prank people with. i shocked abunch of random people at this huge scoutcamporee called peterloon.

http://www.instructables.com/id/Build-a-Variable-High-Voltage-Power-Supply/

 TheMadScientist says:  Aug 31, 2008. 9:41 AM  REPLYearlier somebody said this has the power to drive tesla coils. you need DC to drive a tesla coil. therefore, you cannot.

 burningsuntech says:  Aug 31, 2008. 1:15 PM  REPLYMad Scientist Actually, You can drive a tesla coil with this device cause its output is pulsating DC and yes, it has the power to drive one. As far as theDiodes are concerned, a check on Ebay revealed some serious diodes that would set you back a few hundred dollars if money is no object. A ten ampdiode at 20Kv will set you back nearly $150 and you need six in this configuration. My only question would be where you going to get a case and enoughoil to drop THAT in? Raving Apache

 TheMadScientist says:  Aug 31, 2008. 9:43 AM  REPLYlove the voltage multiplier btw. but you need some hardass diodes once you get further up the ladder. tell me where you find yours please. not microwavegunn's either.

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