On the left you see the TL494-circuit on a pref board, it`s connected to the fullbridge next to it. The 4 Mosfets are clamped to a pentium cpu fan. On the top is the flyback transformer. The circuit is powered by a PC-psu with 12V, in this picture there are around 3-4A flowing.

A high quality picture of the driver, you can see how incredibly trashy it look, but it happily works!

The output of the flyback when the circuit is tuned to resonance, the mosfets don`t dissipate more than 5W. Output voltage is around 25-27kv, not bad for a crappy flyback like this one.

Another nice arc at resonance (Sorry for the bad pic, my webcam sucks) It makes a strange sound, like if you blow air over a bottleneck but a little bit higher pitched.

Now i turned up the frequency a little bit, there is more current in the arc but the Mosfet heating increases. (maybe they have to switch more current now because it`s drifting out of resonance - hardswitching)

Frequency should now be in the 30-35kHZ range. A very hot arc and a lot of mosfet heating - at least 15W but there should be at least 70W in the arc. A AA battery is lying in the background.

 

The circuit, for more info click here

 

 

In this picture you can see a small ferrite transformer to the right, it`s from a PC-power supply, I cracked it open, wound 5 turns of thick wire for the primary and a few hundred turns of 0,25mm wire on several layers well isulated by adhesive tape. It puts out no more than 1 or 2 kV but I can draw really nice bright, hot arcs that can be stretched out to 1cm. I measured the short circuit current to 85ma! It`s really fun to play around with that arc, and the best the heatsink stays cold, it can be ran as long as you want without overheating. It runs off 12V @ around 5-6A and would be ideal as cap charger or with a CW multiplyer as HV-source

visit my homepage - www.lama-online.tk