Re: Double flyback driver??
uzzors2k, Thu Aug 03 2006, 11:09AM

It says "the rest of the schema is identical with that found on powerlabs.org." Since I know the site finding the schematic wasn't hard. Just read through this page http://www.powerlabs.org/flybackdriver.htm and you should be able to make it work.

Re: Double flyback driver??
vasil, Thu Aug 03 2006, 01:55PM

The last schema:
http://www.geocities.com/teslina/dblfpage.html

but....

with 2-3 DC flybacks in serie driven by separate Mazzilli drivers longer arcs can be obtained. Philer did it.

http://old.4hv.org/index.php?board=18;action=display;threadid=5167

Re: Double flyback driver??
FaLLoUT, Thu Aug 03 2006, 02:24PM

oh... yes yes i been on powerlabs before il do it from there... but it says "identical" apart from the two joined flyback parts is it all the same?

Re: Double flyback driver??
FaLLoUT, Thu Aug 03 2006, 02:43PM

hmmm from what philer did i can see that he used two seperate ZVS drivers... From the site i got the idea from he uses 1 single driver and uses 2 flybacks as a big single
flyback which metod should i use?

Re: Double flyback driver??
Steve Conner, Thu Aug 03 2006, 03:29PM

Oi! Fallout: The board rules say no double posting within 48 hours.

Re: Double flyback driver??
uzzors2k, Thu Aug 03 2006, 06:06PM

I beleive it's the same just use the gate winding for feedback and power for power. Use the schematic vasil posted though. Infact go for the ZVS Driver if you want to spend a little extra, the arcs will be much more impressive.

Re: Double flyback driver??
..., Thu Aug 03 2006, 06:12PM

It should work with a normal, unmodified, driver like that on powerlabs (I hate to refrence Sam for the 2n3055 since he had no part whatsoever in the design, but...).... I would recomend that you try winding the feedback coil arround only one of the flybacks, it should give you better stability (and let you usee flybacks that aren't exactly the same).

Re: Double flyback driver??
vasil, Thu Aug 03 2006, 07:02PM

The driver is "almost" identical. The original schema was with 2N3055 (too weak), Sam used a MJ transistor, I used KD. Just use the power transistor you have around.

But Mazzilli drivers are the best for high power output and intense arcs:

http://www.geocities.com/teslina/Rfly.html

...and a variant with separate gate source:

http://www.geocities.com/romtcb/groyer.html

Just choose......

Re: Double flyback driver??
FaLLoUT, Fri Aug 04 2006, 08:38AM

Sorry for the double post i didnt know. I will start with powerlab driver first and then do ZVS driver. I will only try first 2 then 1 feedback windings. If i use 2 2N3055 transistors in a darlington connection and use heatsing+fan cooling (because i have 2 2n3055 now) i think it should be fine.

Re: Double flyback driver??
uzzors2k, Fri Aug 04 2006, 08:45AM


Use three windings, but on only one of the flybacks, instead of both.

Re: Double flyback driver??
FaLLoUT, Fri Aug 04 2006, 09:59AM

3 feedback windings, how can that be when there is only 2 flybacks?

Re: Double flyback driver??
uzzors2k, Fri Aug 04 2006, 11:06AM

My bad, I meant turns. 1 winding consisting of 3 turns, wrapped around either one or both flyback cores. Hope I didn't confuse you too much.

Re: Double flyback driver??
Part Scavenger, Sat Aug 19 2006, 04:23PM

Hey guys, I've had great results just paralleling primaries on the same ZVS driver. I've done up to three in parallel with great success, then depending on what you want, you can series the flyback output for high voltage or parallel for more current. I went up to about 100kV, it was pretty scary.

Re: Double flyback driver??
FaLLoUT, Tue Aug 22 2006, 07:24AM


wow that sounds nice so.. i start gathering a LOT of flybacks and driver parts Do you think its better spark show at series or paralleling the flyback outputs? or maybe i can like go for series and parallel

Re: Double flyback driver??
Part Scavenger, Tue Aug 22 2006, 11:23AM

Nope, it's a lot more fun to series them. Just be careful and just use a long chicken stick (no more screwdrivers). I wouldn't worry about parallel unless you're trying to drive a tesla coil or something, the spark is plenty hot enough for a good show. (at least mine was). I was using IRF540 MOSFETs for the ZVS driver. They died after a while when driving three in series, but I was seriously overdriving them.

Oh, yeah, I was using an oversized (like 1uF) cap and 25V input, with a large filter cap across the input if that helps anyone. Sorry, I didn't measure wattage, but the arc would initiate at about 80-100kV and then the arc looked like it was doing some 30mA or so. I know I wasn't pulling 3kW though, so I assume the output voltage dropped considerably as soon as the arc initiated. Anyway, good way to kill an afternoon.

Re: Double flyback driver??
Wilson, Tue Aug 22 2006, 12:47PM


Is this with 3 similar ones? Also, these didn't have the internal multipliers did they?

Re: Double flyback driver??
FaLLoUT, Thu Aug 24 2006, 01:32PM

Hmm i am definately going to try these flybacks in series. About internal multipliers and stuff.. if you cant use flybacks from new model TVs (that is what was mentioned on the web site that gave me info about flybacks) then what model or what production date TVs should i look for.. Pls help me on this one because all the flybacks i can get hold of are new models and i am searching for a black&white TV now

Re: Double flyback driver??
uzzors2k, Thu Aug 24 2006, 02:11PM

Multiplier flybacks work fine, its just that the older AC flybakcs are often prefered. The old AC ones give better spark length and arcs so I've heard. I've had good results from a monitor flyback + ZVS driver + just 12volts, so use what you can find.

Flybacks

Re: Double flyback driver??
Wilson, Thu Aug 24 2006, 02:36PM

Old ones always seem to flashover and die first....well, for me at least.

Re: Double flyback driver??
cbfull, Fri Aug 25 2006, 01:48PM

The newer ones with the rectifiers chop off half of the AC signal coming from the secondary, and this reduces the overall current. The AC flybacks allow more current and the spark is "hotter" which typically allows it to be drawn to a longer arc once it is struck.

The AC flybacks are the ones to use if you are constructing something like a plasma globe or a multiplier. Rectified (newer) flybacks are great for charging high voltage capacitors. There are other applications for either type but I only use my ACs for plasma globes and for studying inverter circuits.

Hope that helps.

Re: Double flyback driver??
FaLLoUT, Sat Aug 26 2006, 10:04AM

Great i can get like 20 from my uncle next door (he fixes TVs) and he maybe can find me an older one.. well il just use it for sparks and burning things until i am satisfied and then i might concider using it for a plasma globe or some project :)
I guess i can bypass the problem of a new flyback outputting lower voltage by just using 2 new flybacks instead of 1 old AC flyback.. So you say that monitor flybacks are better? in what way are they better? Becase i have a 15" hanging around at my house.. oh by the way my uncle has an old ocilloscope in his yard he can give 2 me can i use the flyback in that for anything cool?

Re: Double flyback driver??
Wolfram, Sat Aug 26 2006, 12:10PM

Newer flybacks are way better for generating large arcs/sparks than the old ones. The old ones don't handle too much voltage before they flash over. Monitor flybacks are weaker than TV flybacks, simply because monitor CRTs require less voltage and current than a big TV. DON'T take the flybacks out of scopes, a scope is a hundred times more valuable than a flyback for an electronics/HV hobbyist. And scope flybacks are usually very small too. Some scopes don't even use flybacks, just voltage multipliers.

Re: Double flyback driver??
FaLLoUT, Sat Aug 26 2006, 12:53PM

The osilloscope is very very old.. it is like from... 1970-80 or something i guess.. Ä°t has been under rain and sunlight for 5 years and it is falling apart so.. i think that would be the best thing to do with it rather than shoot at it with a air gun

Re: Double flyback driver??
Part Scavenger, Sat Aug 26 2006, 05:39PM

Here's the deal with flybacks. You'll hear that DC's(modern) are better than AC's(old) and vice versa. Some DC flybacks output wimpy sparks and others don't. Other times it's the driving frequency that makes it have poor performance. That's why you hear of better results on either side. Generally, the bigger the TV/Monitor, the move voltage you can get out of the FBT.

Plasma globes can only be driven with AC current, so you'll need an AC flyback. If you can't get one, you might be able to disable the diodes in a modern flyback but its really hard and the flyback usually dies soon afterward. (see "Flyback Diode" in the archives). You can also pull the core out of a DC flyback and wind your own. (Easier. The center of an AOL CD is the perfect size for the former)

An AC flyback usually looks alot different than a DC, and it usually has a diode about the size of a pencil connected between the tube and the FBT.

You can drive a flyback from any TV, don't worry about model#.

In general, DC flybacks have gotten me higher voltages because the AC ones will arc over. Generally they seem to be more fragile as well. I think if drive an AC FBT unloaded, this will contribute to it's demise. BTW, I've never completely killed a DC flyback.

BTW... Yes, I was using DC flybacks with multipliers. Similar? Not really, but it helps.

With the ZVS driver make sure you have over 10-12V driving or it won't oscillate.

Re: Double flyback driver??
FaLLoUT, Sun Aug 27 2006, 07:54PM

Thanks a lot for the advice. You said like 10-12v driving is minimum what will be maximum? is there a way of roughly
telling what a FBT can take? In other websites they said 26 volts is for old flybacks (well i am not afraid of killing a flyback i have plenty lying about)

Re: Double flyback driver??
Wilson, Sun Aug 27 2006, 10:02PM

The maximum Vin is limited by your mosfets/igbt's voltage rating. They see pi*Vin across the DS, and you should add a safety margin to that.

You know when you've reached the max of a flyback when you can boil water on its surface
The interesting thing with flybacks is that the output voltage isn't totally dependant on input voltage- as the output is mainly dependant on high voltage spike which appears when you switch current quickly through the primary. As such, a full bridge running at 30V could produce the same output as a TV driver, in which i believe rectifed mains (or perhaps ~200V) is switched in with 1200V transistors.

Re: Double flyback driver??
Part Scavenger, Sun Aug 27 2006, 11:44PM

...or melt skin. Wilson's right, theorically, there is no limit to Vin on the ZVS driver as long as the driver components can take it. The flyback is the least limiting factor.

Re: Double flyback driver??
..., Mon Aug 28 2006, 01:11AM

Just make sure you have enough inductance in the series inductor...

Also, you must realise that the number of primary turns greatly affects the output for a given voltage... Halving the turns is about the same as doubling the input voltage

Re: Double flyback driver??
FaLLoUT, Tue Aug 29 2006, 06:27AM


So you mean that dropping the number of primary windings means more higher output voltage on a flyback?
-----------------------------
And something else, i see different codes like NE555 on timer IC's. Are all the ones that have "555" do they do the same thing, or does it matter if i use any kind of 555 in a timer?

Re: Double flyback driver??
..., Tue Aug 29 2006, 02:20PM

Generally it does... But more often than not you will get more current out the flyback, as the max voltage us usually limited by the breakdown voltage of the switch...

As to the 555 codes, for most applications any one will work. If you are running at a voltage >5v or frequency >500khz you need to type the exact code into alldatasheet.com to make sure that it can handle the voltage/frequency (the cmos versions can't handle as much voltage and the ttl versions can't handle as high frequencies)

Re: Double flyback driver??
Part Scavenger, Tue Aug 29 2006, 02:52PM

...and look at current output if you're driving something other than other IC's.

Re: Double flyback driver??
ragnar, Tue Aug 29 2006, 03:23PM

Double flyback drivers are for wussies...

..but if you can't make a quadruple flyback-brick, you can still have fun pushing a single one to its inevitable doom. ^^

Re: Double flyback driver??
Part Scavenger, Tue Aug 29 2006, 11:04PM

*Wuss bows to the flyback man*

Re: Double flyback driver??
FaLLoUT, Wed Aug 30 2006, 08:27AM

Ok i will look up my 555 before i buy it. Ä° just tried a DC rectified flyback with a real simple driver using a single 2n3055 transistor. Ä°t was a single transistor driver with 2 resistors(how simple can you get?). Ä°t did a 2" spark at 24 volts but after 5 seconds the transistor got VERY hot and died out. After that i killed another the same way . Its so hard to wind DC flybacks primary and feedback windings... There is no room to wind the wire efficently is there an easier way? When i made arcs from the HV outputs there was big arcs from the connectors of the flyback. The singing sound they make from frequency is so nice..... i just love it

Re: Double flyback driver??
Part Scavenger, Wed Aug 30 2006, 11:21AM

Transistors dying with the 2n3055 circuit? Oh, that's normal. That's why it's cool for a while and then we switch to the ZVS or scopeboy circuit.

Sometimes you can chew more plastic out of the way, or take the core off to wind, but it's usually just as easy to poke it through.

Re: Double flyback driver??
FaLLoUT, Wed Aug 30 2006, 01:38PM


i poked it through but it wasnt really a nice winding. It was very hard to poke the insulating tape through aswell. i am switching to scopeboy i got it all printed out here i will start on it as soon as i get all the parts but i am afraid that my flyback is badly wound anyway.. no one is born as a expert