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Hello Jon, You may be looking for somewhat conflicting objectives if you want to create a fast transient (a pulse generator) but also want to form and maintain an arc (perhaps a HV AC or DC source). Perhaps you could describe the failure mode you're trying to recreate - is it a problem of improper equipment operation due to noise pickup or actual damage to the equipment? Following are some ignition coil drivers that may work for your application. The more powerful versions use a relatively high voltage source (100-400 volts) to charge a small energy storage capacitor. The capacitor is then discharged through the LV side of a HV transformer (such as an ignition coil) through an SCR, TRIAC, or power transistor, generating a high voltage pulse. A simple driver can even be made using a 400-600 volt 1-3 uF oil foil-film capacitor (such as a "snubber cap" or "motor run" capacitor) in series with an inexpensive incandescent TRIAC or SCR lamp dimmer and an ignition coil. Be careful - many of the above approaches can generate relatively powerful high voltage pulses. Good luck and best regards, Bert
: I have looked at a number of schematics on the Web but would like some
: expert advice. I am trying to re-create a failure mode in a piece of
: electronic equipment that we believe is caused by a fast transient
: discharge. To simulate the real world problem, I started with an MSD
: Blaster 2 coil (rated 45KV max, 1:100 turns ratio) and a relay to simply
: pulse the primary voltage, which is a 120Vdc power supply that current
: limits at about 2.5A. BTW, I had to use a relay switched manually
: because, for some reason, the 555 500Hz oscilltor I built as a driver was
: getting loaded down. Perhaps using isolation, such as a FET or IGBT,
: would be bettter to drive the coil with rather than the 555 output
: directly.
:
: Anyway, this setup generates a spark of about 1/3 of an inch to ground
: return. OK, not bad but I need a lot more energy. So, I figure I need a
: capacitive discharge to dump a lot of coulombs quickly. However, ideally
: I'd also like to be able to maintain the arc as long as I want.
:
: Can you give me some safe and reliable circuit ideas? What I built is not
: giving me enough "juice" to re-create the problem.
:
: Thanks.
:
: Jon
http://www.rtftechnologies.org/emtech/coil-driver.htm
http://tesladownunder.iinet.net.au/Other_HV_stuff.htm#Ignition%20coil%20sparks
http://www.geocities.com/CapeCanaveral/Lab/5322/simpleign.htm
http://www.geocities.com/ResearchTriangle/Facility/9209/schematics/ignition.html
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