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How To Build A Simple But Powerful Flyback Driver

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Step 5: Power her up and set wires on fire!

When you first power on your ZVS driver, start with 12v input to make sure everything thing is working. Then you can increase the input voltage up to 36v. You can power the ZVS driver above 36v, but then you risk blowing up your driver, check step 7 for instructions for modifying your ZVS driver to handle higher input voltages.

You may hear an very high pitched squeal from your ZVS driver, don't worry, that is normal.

What ever you use as your negative terminal, it will get hot, very hot! The arc will melt any thin wire you use into little metal balls and steal will just fly everywhere, which is cool (and dangerous)! If anyone has a good explnation why the negative terminal get so hot and the positive terminal remains fairly cool, I'd like to know.. :-)

Also, in the video, just after the arc burnt a hole into a lightbulb, they was a stream of plasma 'shooting' out of the bulb, like a flame thrower. This is because when the arc got inside the bulb, the gas inside heats up, causing it to expand and escaping through the hole thus creating a "plasma thrower".
 
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fatevian1 year ago
Hi everybody!
Someone can clear me a doubt?
It works if I put a HV diode to rectify? Do you think it's possible with this circuit, to supply high voltage to magnetron oven? What do you think?The current is strong enough to break down the barrier of diode?Thanks.
Jimmeh302 years ago
Virtip, has it right with regard to why the NEG terminal gets hot, the easiest way to wrap your head around (IMO) is to read up on tig welding.

The answer's regarding accelerated Ion flow are the more correct answers tho, given the HV field being generated.

Quick question tho, I built one of these with IRF450's, fired it up and got nothing. I now know that the input inductor I wound is FAR too large but, are you supposed to remove the air gap from the core of the flyback? or does it need the air gap to "fire"

cheers.
skrubol3 years ago
Are you rectifying the output? As this is a transformer, it's output should be pure AC, therefore no positive or negative.
Normally on a DC arc the positive will get much hotter than the negative (at least 4x more heat I believe.) Plasma cutters always have the work piece at + polarity, and tig as well. Arc (Stic, SMAW) can run either way depending on what you're doing (whether you want to melt the base more, or add more filler,) and I believe Mig/wirefeed is usually workpiece - (electrode positive.)
doepy3 years ago
my theroy the ground gets so hot is that the hv is drawn towards it therfore the the heat goes with it
nakarti3 years ago
After reading the multitude related links in Wikipedia, it seems the ion accelerator is the best explanation of the negative terminal heating up more, with the electron stream crossing the shortest path...
_BiG_3 years ago
Why get hotter the negative electrode? The answer is quite simple: when the air breaks down the molecules separate and produce free electrons and positive ions. These particles are accelerated by the high voltage field. The electrons run towards the positive pole and the ions run towards the negative pole. The ions are more than ten thousands heavier than electrons and can give much more energy to the electrode when impact. This energy is become heat.
virtip3 years ago
i cant give you an exact explenation as to why the negative electrode gets hotter than the positive, but i do have an example.
on a dc welder, the handle used to weld with is commonly made as the negative electrode, not becuase the welding handle gets hot, but becuase the handle stays cool and the positive electrode (the piece being welded) gets hot as hell,
the inverse is true when the polarity is switched.
and as to not doing this your first time, im going to go with this project for my first flyback driver becuase i think i have all of the necessary parts, except for the MOSFETs, i have two computer monitor boards (flybacks harvested), a large scanner power supply (circa 1980's), and the parts from two microwave ovens. think i may have found some MOSFETs in the scanner power supply, but im not an expert at identifying MOSFETs and searches on the part numbers on the cases turn up random pdf garbage that i have no hope of wading thru. help?
part numbers are:

Toshiba C5339 (monitor control boards)
STPR10
BYV11h
Hi there. I tried my ZVS driver that I made a couple of weeks ago now and I connected it up to a 12v SLA and I turned it on, but I got no arcs at all. I checked the direction of the windings, they were fine and the inductor and MOSFETs got warm, but still no output. Can someone PLEASE help me? Please? I'm so desperate to get this working...
dgcoffma4 years ago
thermionic emission
I finally got mine working tonight. Great Instructible!
i think the negative gets so hot because the electrons flow from - to + (Ive tested it) and it hasn't had resistance with the air