Tuesday, June 26, 2012


MY WORK CONTINUES ON "Mostly Macros Imaging" but I will begin posting here again as long as this blog stays well.  I will just keep my new blog as a backup and transfer at least my main first post onto this one.  I have a lot of work to do.  I have been working on electronics and photos of my projects--I have built many in the past few months! I have taken 100s of photos which have not yet posted.  It is a lot of work and so it will take a while before I am ready to post them and I have this blog problem fixed.  There have also been some family issues that have been difficult in recent times--I will somehow transfer the posts and post many more pics of my electronics, including my TUBE (6L6 GC) flyback driver.  I am building my timer mosfet driver into a clean and small package as well.  I will update this blog as soon as I can starting with the posts done in my other blog.  I have also not contacted some of my friends lately, please forgive me for that I have a lot going on.

The most important news here is that I got a call today saying this site was BACK on line!  After a serious crash and then blackout--I assumed that my blog was basically history.  I could not even access my Google account.  In turn I made a new blog called Mostly Macros Imaging which I may import or continue to use I am not sure.  I may just put a link into this site.  I will wait and see if this site remains stable.  It is very possible that Goggle simply had an error that they did not tell me about which may have had something to do with the anti-virus program that claimed many blogs were fake. I do not know, but if this site keeps stable--I will continue to post.  I had figured that all these years of work and pictures were gone.  It all came back and it looks like Google got the problem fixed!  It will take me time but I will at least post a link or move the articles from my new site into this one.  I am not sure how I am going to handle this yet.

--old news--
NORTON ANTIVIRUS SERIOUS NOTE:  I plan to put more electronics in my site--and articles--as well as new photos.  However I was shocked to see that blogspot experienced a SERIOUS PROBLEM WITH NORTON.  It says that my blog and most other blogs as well are "counterfeit" or something to that effect.  With a huge warning and some people even say they cannot access there site at all.  I had to shutoff Norton.  This is a BIG DEAL effecting 1000s of bloggers.   We are mad a NORTON and hopefully they will have the problem fixed soon.  They are apologizing--for what may be a serious problem which they claim was fixed but keeps happening for me at least.  I am sure that means they will fix it soon.  They say it was a total error-- blogs are very safe.  Unless you click on a link--you can't get a virus by going to one.

WARNING!  DO NOT attempt to build ANY high voltage devices unless you have experience in electronics and high voltage.  These devices can be unpredictable, far more complex then they look on paper and of course, very dangerous.   These pictures and basic schematics can be found on the internet commonly and are for educational purposes only.  I am an electronics technician with over 20 years experience.  Attempting to build a high voltage circuit without the help of an experienced technician could be dangerous or deadly.  Other hazards exist with high voltage as well.  I will not be held responsible for any use of the knowledge posted on this site. It is up to you to be safe and smart with any experiments you conduct.

I have not been posting pics because I have been working.  Working on some really AWESOME circuit power supplies.  One is my variation on a simple but effective 40-50Kv (40-50,000 volt) oscillator which uses a flyback or LOPT transformer from an old color TV or computer monitor (the bigger the better) to produce high voltage.  Sometimes very high voltage, a large flyback from a large tube TV can produce as much as 50kv if it is driven right.  This can be used to run experiments, drive plasma generators and many other things such as singing arcs and Jacobs ladders.  You can also build circuits that will double or even triple voltages such as voltage multipliers and Marx generators to simulate lightning.  So to merge my two great interests of electronics and photography I built three main kinds of power supplies for extensive testing. Each has it's advantages and drawbacks.  The first one is a relatively simple 1 transistor Hartley oscillator (HO) circuit that requires a transistor you will almost certainly find in the TV you pulled the flyback out of.   It is rated for high voltage, so unlike many of the schematics on line which call for a tortured 2N3055--you won't have burn out issues if you treat the circuit right.  The 1 HV NPN H.O. transistor circuit can handle the current and voltages used since these transistors are rated for at least 1000volts! The Hartley circuit can handle input DC voltages as high as 24volts or so, going higher may burn out the transistor without serious modifications to the circuit.  Attempts at running it as high as 35volts destroyed the transistor instantly even with current limiting measures.  The flyback is driven to do several things in a TV, it runs the horizontal control for the magnetic yoke as well as generates the high voltage for the tube.  It even often provides the filament voltages needed!  It's the heart of a TV and does lots of stuff.  With the right circuit however, it also makes a great HV power supply.   You can order these HV Horizontal control transistors on line, and they are far more efficient then a 2N3055 in this kind of circuit.  These can be very efficient circuits if you get the resonance right as they operate using a feedback winding.  However, generally speaking they would not be my first choice for highest voltage outputs or amperage. They are however quick and easy to put together with just a few parts and alligator clips.  You will want to use a good heat sync.  See my schematic for part numbers.  I could get VERY technical about all of these circuits as I have been experimenting with them in depth for most of this year.  The articles on my new Blog "Mostly Macros Imaging" (I still don't know when/how I will make them visible on this blog but they soon will be) give a bit more depth to some of the experiments I have been doing. One of them explaining how I built my own flyback able to produce about 10kv and the complexities of coil/transformer winding.  I have learned a great deal about designing high voltage generator circuits with my final goal being to build a 500kv-1million volt Tesla coil.

But I do not just plan to build it, like these other circuits, I plan to understand it's design and take part in that design entirely.  So I started off here with the most basic HV circuits and then moved on to the ZVS--a great circuit for lots of applications and many would argue, the best.  It's biggest limit being that when it is used with re-cycled TV flybacks, it cannot be grounded to earth.  The 2 phase pulse system is very efficient but makes it impossible to put a grounded load on the circuit or even a lot of mass without serious kickback.  Using oil may be the key to fixing this problem--I am now working on that and just began using it very effectively.  Mineral oil is the key to all your un-wanted arc problems!  Most recently the synthetic drive circuit which is a 555 timer or other chip that drives a power mosfet has grabbed my attention.  It is not as efficient as a ZVS but can produce close to ZVS power outputs and has a very wide list of applications.  The same circuit can be used to control a motor, drive a flyback (or even 2 if done right), even drive an old 110 to 20V line transformer backwards to produce 110V again--making an Inverter.  I was able to build my own inverter this way powerful enough to light a large CFL and even a 60W incandescent light-bulb!  I was also able to get it's frequency so close to 60hz I got a clock radio to keep time! Although I admit I would need filters and more stability to get it to really keep time well since cheap clock radios have poor oscillators for keeping time and require a true AC very clean sign wave. But it does work, just keeps time a bit fast and of course the radio works fine.  Learning the abilities of each circuit and how they work as I go along has been a fun and amazing process.  I knew about these circuits but this is the first time I have really put energy into building them and studying them carefully.  I am not without HV experience and of course have a good background in general electronics--but I have never jumped into high voltage this deeply until now.  No matter what you know on paper or in theory, nothing is like actually building the circuit yourself and learning it's possibilities, pitfalls, and options first hand.  This is what makes you truly knowledgeable about a subject.  Hands on experience is very important with all learning.  However when it comes to high voltage--often the operative words are "hands off"!  The main thing slowing my Tesla coil down right now is money--my budget is very low so getting the things required is difficult and will take me at least another year, possibly more.  Looking up things on line as I go I have also dispelled a number of myths--yes you CAN hook 2 flybacks in series. However--you may not be able to unless you use a ZVS since frequency and isolation is a factor in doing this.  And the biggest problem of all with flybacks in series is the HV diodes which are usually impossible to remove.  After you get to about 100kv--the diodes run the risk of being destroyed.  So unfortunately I cannot hook 3 or 4 flybacks in series--DC flybacks anyway--without most likely blowing out one or more of the HV diodes in the flybacks.  One will fail and the flyback is useless.  This limit makes most large TV flybacks probably limited to about 80-100kv.  I learned this all too well when I got a 12cm arc going (at least 120kv!)--it looked a half a foot long!  It only lasted 30sec or so. I now use an idea I came up with a long time ago to protect circuits on all my high voltage drivers.  Just 1 50W 12V light bulb on (+) of your DC input will save you a lot of money and grief as well as show you what is going on in your circuit.  A car headlight insert or those lights you can buy at nearly any store work great.  This gives you a solid 4amps to work with before it lights up and starts to take some of the current away.  If it does--something is wrong, and since you can get 3 for $8 or so--these little bulbs are cheap compared to mosfets lost due to ZVS meltdown!  Even if you power supply voltage is 50V--you can use just 1.  Going higher I might run 2 in series, but even if it does turn all the way on your bulb will act as a fail-safe and visible fuse.  Great for trouble shooting.  Desk lamps and other devices use these little 12v 50W bulbs--they often come with a small reflector built in.  If you want more power you can get 100W by putting 2 in parallel.  They have saved me a lot of money and effort in trouble shooting and I will mention them more later.  One of two flybacks in the ZVS failed when I bypassed my current limiting.  After testing the flyback in a number of ways (even building a resonance jar that will produce a voltage in any coil placed in it) I found the only thing that made sense for it's failure were those pesky diodes and that one of them just shorted inside the flyback once it reached it's peak voltage or got too hot.  I miss the days of tube rectifier HV.  You got an AC or DC flyback and it was YOUR CHOICE when you took the TV apart.  I sure wish I could find more of those today!  That circuit is later--first--check this out. 

"Plasma wall"
This is a Jacob's ladder making a plasma wall--pretty cool!  However--we are not even getting started with arc size.  This is about 40kv.  About 40,000 volts.  Most large flybacks can be pushed to 35-40,000volts without damage.  The same more or less--as most stun-guns and Tasers.  Which also use HV didoes and capacitors to produce a "punch".  I have bought about 6 stun guns over the past 15 years from several different companies and tested them.  Now days, they are saying they have as much as "7 million volts"!  Police, security--and everyone else--should know that this is a LIE!  For reasons I can only speculate they lied after they actually lowered the voltage from nearly 60-100kv in some units to about 40-50kv in most quality units now.  These companies decided to do this after complaints created by "kickback" which was impossible to control due to those large voltages arcing so easily.  You got shocked at the same time you shocked anything else.  Not cool!  Lower voltage however does NOT mean the stun-gun will be less effective against an attacker.  Actually using less voltage and higher current at a good pulse rate is a better idea--and this is why all pretty much all TASERS are 50,000volts.  However, how could they go from saying 100,000volts to 40,000volts!? It sounds bad. People would ask "where can I get the high voltage" when they really need to think about current, voltage, and frequency--as these matter far more then voltage.  But most people think that voltage is everything.  Not true at all. You can get 500,000volts from a Snuggie or blanket in the dryer!  IT does not kill you because it's current is very low.  So I guess a need to counteract useless fear over lower voltage prompted by bad kickback problems with the higher voltage models--they just started lying sometime in the late 1990s or so.  This is simple--and I need only say it once but everyone should know this--the best STUN GUNS you get will only give you about 50,000volts--even if it says "7,000,000volts".  The same (usually less) as you get from a police Taser. So cops should NOT be arresting people because they are selling or having these "million volt" super-stun-guns.  They are not any worse then they were before, no new magic has made it possible to get millions of volts and there is no reason to even try.  I own several of these stun-guns and I tested them myself.  I have been stunned with them as well, so I know!  I have also been a security guard. So trust me when I say from an electronics standpoint--they are just trying to sell bigger and better models and the only way to get to people is to tell them they have "millions of volts" now.  Tests show that often these new even very expensive stun-guns put out only about 30-50,000volts.  Giving a comparable shock and CURRENT to that of a police TASER.   This is important--since this issue has caused arrests when cops thought that you could make or they are selling "super stun-guns" that are thousands of times more powerful!  The only way to make a "super-stun gun" is to build it yourself and it would have to be very clever.  For millions of volts--something about the size of a small bag or briefcase holding large capacitors, voltage multipliers and a driver like a ZVS.  It takes serious technical knowledge to do that.  The parts for ANYTHING that can make millions of volts cost hundreds or even thousands of dollars--so doing it is very difficult and requires usually a very large coil like a 3 foot or more TESLA coil hooked up to very serious vacuum capacitors.  So lets get that MYTH about "million volt" stun-guns--out of the way!  It just is not practical or possible in such a small package.  Not at any useful current level anyway.  Most smaller, cheaper or 9v powered stun-guns I am sad to say, will only give you a hard-buzz and are not likely to knock out anyone let alone repel a mad and angry attacker.  If you get one--and I do carry one myself--get a rechargeable powerful one--and it may say "7 million volts" but it's really about 40 or 50,000volts which is the same as the police units.   Why they chose to possibly harm business with this lie I am not sure.  I recently saw an episode of a show like Cops about this- the cops were afraid of these units and talking about them as if they were very dangerous.  I can't stand it when people are not informed. It is simply a lie to sell more units.  And the lower currents they usually put out are less then police TASERS.  Some of the lower priced models are ok, and will disable someone if put in the chest or neck area.   However--make sure you test it on your leg--and do not buy a DOUBLE UNIT--they tend to go into high-frequency oscillation and loose there kick if both units come into contact with something.  This is no good!   The rechargeable ones seem to be the best--but I can promise you that none of them are a million volts.  Lower still in current, over a million volts is produced when you take tape off a scotch tape roll!  This amperage is so low it takes special gear to measure it and you don't feel anything.  But it can fry sensitive electronic parts.   Many problems would exist with a million volts in a box that small in a viable form--for one thing the diodes need to be larger to handle voltages like that, the coil has to be big enough to produce it at any viable current--and voltage multiplication capacitors at those ratings are very expensive--even in China!  So if you get one--be sure to buy an expensive unit and know that it's only about 50,000volts.  40-50kV is all you need--at the right amperage--to bring someone down.  The electric chair uses only about 2000 volts (at very high current) to kill someone.  So why all the hype about higher voltages?  Current is what kills or harms.  If you live in a state where they are legal, you also might want to brag only about your stun-gun being 50kv--and not have the sticker on it that says is "millions of volts".  Some cops might think it's illegal.  This is all so stupid, since it's really the current and frequency of stun guns and TASERS that bring people down, stun, hurt or could kill--NOT the voltage.  Even so, although it is possible the flybacks in some produce up to 100,000volts or so--arching several inches, it's really not a good idea to attempt to use that kind of voltage in such a small package with cheap parts and tiny batteries.  I knew this all along but even so ordered several different units and tested the voltages just to be sure--I was right.  The highest voltage I have ever seen from a Stun-gun was far less then what my ZVS produces--at far less current.  Way less then half the current.  To sum this up, they decreased the voltage in recent years in order to prevent problems with higher voltage systems in small packages--kickback getting to you.  So I guess they had to compensate by saying the voltage was higher to make people think they are more powerful.  They did increase the current in some units to better levels.  Notice how the prongs in recent years on most stun-guns have gotten closer together?    There is no need to make laws or be afraid of these things--they are very useful for repelling attackers without harming them permanently and should be legal in every state.  Voltage lies continue to keep this from happening in some states.

 This ark is about 1 and a half inches long and was produced by a relatively simple system of using a large Color TV fly-back coil.  Tube TVs require high voltage to produce an electron beam to light up your screen and draw and image on it.  This voltage varies, but most fly-backs can produce more then the TV uses.  So you can get about 35,000 volts out of even a small one.  Fly-backs are far better then ignition coils for raw voltage.  Ignition coils force you to ground one end to the input and are already in oil.  This is good, but upper insulation makes it very difficult to push them as hard as you want.  They are also built for low frequency and higher current making them more dangerous to humans. The low frequency part makes using them for plasma displays very painful! Typically you only get about 10-30kv out of an ignition coil before it starts arcing through it's insulation.  You could put one in oil and probably get 100kv out of it if you pushed it hard enough, but there is a danger of damaging it or melting the wires.  They are very good for anything you want to have arcing all the time as they were built to handle shorting out at high voltage and high current.  It takes some interesting circuits to drive them and I don't want to get even more technical here--if you want info email me or look it up on line, a 555 timer system with a large power mosfet would be a great choice.  They are small Tesla coils but cannot be run at high frequency so they are not much fun for plasma displays.  Like flybacks, despite ignition coils being low frequency--they are built for a DC and they will NOT operate at AC line voltages/frequency--like 60hz. They require a higher frequency.   Flybacks are a great choice for lots of things but the older the better. If you can order an AC flyback on line or get one from a really old all-tube TV--you got it made.  Often these connected to a large tube which rectified the voltage into DC.  SO this cap is your output rather then a suction cup for the tube.  Ground was often just the chassis.  These AC flybacks are an awesome find, a few companies also still make them.  The new ones have diodes embedded in there coils.  This makes the newer ones (made after the 70s or so) only good for some applications.  Since the diodes cannot be removed. However, the older all-tube TVs and some other TVs use a tube as a rectifier or external diode, this small tube will have a cap on it and be connected to the fly-back--this means you are lucky and found an AC fly-back!  Keep it and treat it with respect and care!  They are hard to find now days and great for making plasma displays and other stuff.  IT is nearly impossible to remove the diodes from most modern fly-backs.  However, arcs and many projects can be produced even with them in place and for some projects the DC is preferable to AC.  I use the arcs for photos and plan to post many more now that I have the power systems built.  This is one of the first schematics I drew of my 1 transistor Hartley design.  It came from an internet design which I modified to include a better transistor and use the flyback's internal windings rather then winding your own external ones.  There are some very serious reasons why you should NEVER break off those pins on the bottom of your flyback or cover them up!  The arcing can be controlled by using hot-glue or better yet MINERAL OIL.  Just submerge the entire thing in it, and run leads out of the jar it's in with hotglue to seal it up as much as possible.  Good Tupperware containers work for this, I will show this later.  This lets you run flybacks as high as they can go without any arcing that is not wanted and do things like run them in series.  My new power supplies have flybacks in oil just to make it more easy to control and use.

Here is the schematic.  Sorry about the light, I draw my schematics in pencil and don't have the software to make them on computer yet.  I have been hand drawing them for 20 years so I'm used to it.  This was my prototype basic schematic right out of my notebook--lacking lots of details or really nice drawings--so forgive the possible things left out but I assure you if you follow it it will work.  I found that you need at least 5W-10W resistors for the 220ohms and be sure to get a high voltage transistor from an old TV--you will clearly see it, usually it' marked with it's contacts and most of them are NPNs.  It will be connected directly to the fly-back in the TV which is drives.  So it's only natural to build the driver out of the transistor from the same TV!  Just because part of a TV died, does not mean the rest of it is.  Dead fly-backs and driver transistors are relatively rare.  The driver transistors are so difficult to turn on it takes less then a 10k to turn it on!  Once this circuit is going, hooking it to a power 20W 8ohm resistor is a REALLY good idea so that if anything is wrong you wont' fry everything.  Then use a good supply, regulated or high amperage--to run it.  Don't run it above 24-26volts.  I HAVE TRIED and trust me the transistor will fry unless you re-design the entire circuit.  Be SURE to use a heat sync and remember--the wires in the secondary (high voltage winding) of a fly-back are thinner then a human hair!  if they break or short--that's it. So don't arc it into oblivion if you want to keep it going. Check temperatures and only run large hot arcs for a short time.  You will have to find the leads here--this kind of circuit does not work very well with an external winding done yourself.  The hardest part about building this circuit is probably finding the right leads to use.  You need the primary coil--usually off by itself shown on the bottom left--and then you need the feedback coil--one of the other coils in a fly-back that will work as one.  This makes for some great output. You can wind your own--but as I say it's better to use the fly-back's windings as they are setup really well for this kind of driver. You just need to locate them by experimentation.  Polarity of BOTH sets is very important and must be right, so use a large resistor to find out if your circuit is working and find the leads without damaging anything--like a 50ohm, and an EMF meter--and then alligator leads to see when it starts to oscillate and produce a bit of high voltage. If the secondary is wrong a tiny high voltage may come up--be sure to test both directions while in a test mode (using a 50ohm series resistor) Then kick up the voltage and remove the 50ohm current limiter. You will either hear a sound and get almost nothing--or get lots of high voltage and hear a sound.  If you hear a sound and get no high voltage--reverse BOTH of the primary coils polarity and you should get things running.  The high voltage should hiss and then draw and ark--you will also need to short out the two pins usually close to the focus module.  This is a large coil that is connected to the secondary and thus must be hooked up.  This is true with every flyback I have seen.  In fact you find ground by seeing what pins arc together first at the lowest power input, short them and then solder on a wire and that's your HV (-) .  As far as using homemade coils--for feedback they will work fine in fact playing with this you could get to the resonant frequency of the flyback and produce a really high output--but wind the whole thing?  It works, but not very well.  If you wound A LOT of turns on it maybe--but it's best to use the fly-backs built in coils for this one.   Kickback volts will happen depending on your load and setup--use a 10k and 0.1uF cap for that in several places and or large MOVs. There are other ways but this transistor is so tough that you can operate it for a short time with the leads arching from emitter to base to collector!  I've seen it!  You will want to KEEP ALL ELECTRONICS including your phone and laptop--AWAY FROM THIS CIRCUIT and any other parts you intend to ever use again. IT produces a very active electrostatic field due to the low frequency oscillation it makes.   So it can fry things at a distance.  Don't get your digital camera or laptop too close!  Once is all it takes.

THE AWESOME ZVS!  (Zero Voltage Switching) driver-->

Several names are attached to this circuit which in itself is also pretty simple if your not a beginner.  This circuit was apparently designed by Vladmiro Mazilli according to the internet. It is basically just a push-pull mosfet oscillator with a lot of advantages and uses.  There are several versions including the one shown here which is my take on it.  I changed several component values and added a 2nd fly-back in series--breaking what many on line said was impossible.  And this is not just an effect due to 2 identical or lucky fly-backs--I have tried this now with 2 other fly-backs and it works just as well!  The ZVS may be the most powerful, versatile and trust-able, circuit for high voltage production.  Great for lots of stuff.  It produces lots of current, and lots of voltage from a fly-back or as I have proven is possible--two.  On this circuit you want to keep things to about 22-40volts and no more unless you change values.  At that voltage range you will have a lot of fun!  I found that hooking 2 fly-backs in series is just a matter of frequency and making sure that your ZVS is setup for it.  There is only 1 ZVS driving both fly-backs the ballast 12V 50W lamp which is in my schematic--I will add here soon.  I will put my schematic up in full later when I have it properly photographed.   As you can see, power is just pumped into the flyback with a coil of wire, 3x3 or 4x4 turns should be fine. Keep leads short and neat, despite what my circuit looks like!  See my finished supply--the CD-707 for a full system that works well.  This one is the prototype only.  The capacitor MUST be directly connected in the system.  In other words--if one wire is 1in going to one drain, and the other is 3 inches--it may not work!  One must experiment and build a clean circuit if you want it to be stable. Depending on lots of factors including your DC supply voltage and frequency--more turns might NOT be better.  I find 3x3 to be more then sufficient at AWG #22 hookup wire. Just be sure to use large insulated wire, it will get hot even if you do.  One flyback homemade winding is center tapped and goes into an RFC.  Be sure to chose a powerful one (2amps+), a 100mH I got at Radio Shack worked fine.  This choke the drain capacitor and the resonant frequency of the coils you use direct the operating frequency which can be quite high.  Unlike other kinds of driver's--the ZVS automatically will tend to operate towards the high end of a coils resonant frequency and pulls little current when nothing is being used.  It's a very efficient circuit.  It also does not create very much low frequency static/harmonics and does not use any part of the flybacks own primary except the ground end of the high voltage--so connecting them in series is easy since the homemade primary coils are isolated from the flybacks windings electrically.  Use a strong wire with good insulation and put in an oil filled tub as a separate unit to contain the HV DC electrical field for best results.  Out of oil they are limited to the flyback's insulation capability.  Regular mineral oil available at almost any drug store will work. Kickbacks can burn through this insulation so be sure to use hot glue at the bottom to cover the core so that arcs do not get into it and thus make it through your insulation on the primary wire if you are not going to use oil

I have lots of advice but I can't put it all here.  The complete computer-drawn schematic for this will be shown later.  My version became different from the version I got off the internet and drew on my notebook, but that is a start and that will work for one flyback.  First off, if you get those $3 Chinese bread boards--remember--each terminal is not like in the USA!  The terminals for power on top and bottom are only connected together every 2 x 2.  So you have to put in jumpers or you might spend hours wondering why your circuit does nothing at all!  I tested every part and only when I'd tested everything did I figure this out!  The capacitor is around 0.22uf and remember it gets HOT! Use a large one HV AC cap. and short leads. Find the right one, at least 200v. 0.2-0.7uf  My biggest peace of advice is to get a large current limit device--like a car front headlight--the 12v 50W ballast bulb.  You can find them in many places that are small now days so they won't take up lots of space.  They pull about 2-5 amps--so your circuit won't even be very limited unless it has a problem.  This circuit needs some serious amps to get going--most on line articles say "lead acid batteries"--like car batteries-- laptop batteries would be great but they must be modified first.  Laptop batteries may overheat or switch off, possibly even blow fuses if used with this circuit.  I use a Variac that is fused and bridge rectified to give me a large choice of voltages but do not go too high!  Above about 40% or so could damage flybacks!  They die very fast.   As I say--this 12v ballast bulb saved me more then once--to make sure you don't destroy all your components when you have a failure.  Experimenting with a new circuit there always is one problem at least!--use a 12volt car head light or desk lamp 50w 12v and your good to go. If it glows at drawing an ark then it's at the right time and you will know when your circuit is running well, it will glow slightly like a radio tube in normal operation--even at 45volts.  If something is wrong, it will light up really bright or even blow out if your using really high voltage and no other current limit systems--I use a good 3ohm 25w resistor at least too--ceramic so it can stand higher levels to protect everything a bit more.  It is not only a valve to stop wires from melting (and at these amps needed they can!) but it will stop one burned out part from cascading into another and burning it out.   The whole thing would have gone up in smoke twice now had I not used this method.  If you really want to see it fly and possibly fry, and add about 2cm to you already insane 8-10cm arks--remove it for a moment.  But watch temperatures.   The 2W 470s should really be 5W.  I changed that to 1k as they overheat quickly.  Whoever designed this circuit should have realized that.  The Zeners are there to protect the mosfets from exceeding 20volts on the gate. Thus they can be as high as 18 volts or so.  I use 1N5353 There are lots of cool things about this circuit but it requires lots of power, so I built an 4 level power supply for it.  Here I have 4 settings from about 10kv to 100kv on the system in a relatively small box for this many required amps.  2 switches control the DC output.  (In this case I am not using a Variac) Current limitations should be used for high voltages over about 100kv (10cm sparks that START at 10cm NOT draw out to 10cm!) you run into problems that might fry smaller fly-backs.  Don't push things too far or too long, using one flyback, I would not exceed an operating voltage of about 24 volts.  I am not sure you can push more then 2 fly-backs at once.  If you could you might be able to get a foot long arc, but I am afraid that may not be possible due to limits of flyback construction due to those HV diodes.  For unwanted arching at the bottom--use hot-glue.  Or just submerge both of the fly-backs in transformer mineral oil.  It can be removed and it is nearly a perfect insulator, non-toxic and has no odor.  So it stops arching very well.  Hot glue is also a great insulator, I use hot glue all the time and it's really cheap.   I would NOT break off any leads to stop arks as someday you may want to use those flyback leads in another circuit and really regret it.  Start out at about 22volts, no more.  If you start too low the circuit may not start to oscillate on it's own.  Keep leads to the hart of the circuit--the capacitor across both Drains (0.22-0.7uF 224-704-capacitor code numbers ("XX4"=0.X)--short.  Many of these can be found in computer monitors and tube TVs.  This part must be in good shape and checked heat, the circuit will do nothing without it.  And be sure to use a heat sync on your Mosfets. I use IRFP250s and have gotten used to them.  There are several kinds with different prices and sizes, do not use smaller power mosfets without checking specs!  IRFP250, 260 and 460 all work well.  Mosfets are actually also STATIC SENSITIVE so make sure they don't get too close to the HV.  The diodes are  FAST diodes--you can order them on line.  400+volts or more. (example:UF4007 --NOT 1N4007!)

Here we go-- 100,000volts or more.  Better pictures to come as they are already on my alternate site.  It is difficult to tell without about 300 mega-ohms.  I am working on that to get really accurate high voltage measurements.  I currently can measure only up to about 40kv.  The output here is near maximum but it will put out a bit more if I pushed it too far which might fry a flyback.  Use 2 large (30+ inch tube TV) ones if your going to use 2.  Be sure to get a good idea of what you can do with 1 flyback first!  I got the idea to prove and see if it could be done since I read so many people on line saying it could not.  You just have to take some special precautions and do things right.  Problems have already happened once.  My arcs for a very short time reached nearly 15cm-cold start!--but one fly-back stopped.  It took me hours to figure it out but when I did I was surprised after seeing so many high current large arcs pulled on U-tube out of sometimes small flybacks.  I have heard of other people blowing up flybacks, but usually it's from charging them with the wrong kind of power (like a 12v transformer or even line current!) --or using a ZVS to push them way too far or just letting it arc to itself or the core.  Often these videos are done however, without a ruler or stuff to really show size, so I thought I would prove my 3-4 inch ark--with one.  

 Here is another picture.  The ark is less then 2 inches from the ruler.  Showing how long it is to some degree.  The picture below is even better.
 Here we see the ruler being shocked with two arcs, this is because as you might know--old style wood rulers have a metal rod at the end of them for drawing lines.  This metal was a quick find for the HV which made it there very fast at 100,000volts!  This would be a "super-stun-gun" but look at how large it is!  You could not fit it in your pocket!  You can't run something like this off 9V batteries for long. This thing pulls at least 2-5amps at 40volts with the car headlight as a current limit 12v 50W X2-- and 3ohm power resistor.  So the power draw is about 80W+--most probably 150-300W or more with less current limits.  As I say, be careful, even with current limits, running this for more then 1min or so is pushing the flybacks hard if arcing.  This is built for momentary things like photography, not Jacobs ladders and stuff--but you can build a ZVS for that which will do great.  I even put a relay on it for a small hand operated on-off control.  This lets me arc on or off for photos when I want. I can also hook a CDS cell up to the control board and have it turn on or off with lights.  A simple circuit could also turn it on or off with an IR remote although interference from the arcing makes that difficult to do.  RF control is possible if you use FM or UHF--as long as the arcing does not create too much RFI. Arcs this big are serious and really show power.  You can feel it.  I would not want to be shocked by this, it probably puts out 1ma at full voltage but if loaded ma will increase to as much as 50 or more at less volts but still 10s of thousands. That could be enough to kill if you got hit with the full current.  It is always good to have an isolated safe switch that requires you to push it in so that if you are shocked you will shutoff the device automatically.  Just be very careful around ANY high voltage and unlike these pictures--use some HV cable for hooking things up--as it quickly arcs through the insulation on these kind of leads.  You can get HV cable at auto parts stores.  Ignition wire cable works great.  A simple bifilar-wound toroidal transformer placed on power or one on each gate of the mosfets will modulate it and create a huge singing arc!  I am not sure how long things will hold up if current limits were taken off, temp is good, but the fly-backs are taking a lot of power.  I wanted a big spooky old movie arc, so I came up with a new kind of ZVS for what I needed.  I chose 2 fly-backs that use a small electrolytic capacitor and current limiters to produce less current put more volts--it works great.  This is the largest high voltage supply I have ever built (as of 2012) and I built it from scratch.  For an updated schematic--stay tuned to my site. UPDATE: And my other sites articles will soon be here.   I will also be adding more pics at higher resolution of the arks and things arching into stuff as well as the DC plasma and particle photos I built this for!

This is the basic schematic I started from on line.  I drew it again fast--and have yet to complete and photograph a full version of my ZVS system.   My revision now includes a redesign of this circuit that allows for more power and a variable output.  The CD-303 and CD-707 homemade lab supplies. UPDATE: I have now drawn on computer my version of this circuit for running 2 flybacks and it will soon be posted here with more pics.  It differs in serious ways from this one, but the basic principle of a ZVS is the same.  You can get large and awesome arks with this circuit.   This is right out of my notebook.  There are also many on-line resources--just Google "ZVS driver" for those articles. Click to view schematic better. If you have any questions please feel free to ask.

And here is the prototype in full operation!