rp181 wrote:put a LED in first to test it, way easier to debug if you cant use the comp o scope. Tell us if anything goes wrong. make sure the capacitor is correct polarity, thats a common mistake and will cause the led to stay on. You might want to put 2 pots, on for pulse length and one for duty cycle, it will asjust rate of fire and power of shot (longer pulse = more power to a limit)
jimmy: I have a diode (fast recovery 200A 1200v (5200A surge)) but by preventing ringing, pulse length will be shorter, and wont suckback as much.
The LED is a good idea (you'll need a hundred ohm or so resistor in series with the LED and you won't be able to see cycle rates faster than perhaps 10Hz (cycles/sec). Remember that LEDs have plus and minus leads, hook'
m up backwards and they won't work. You could also hook the output up to either a small speaker or to a piezo transducer. Record the sound with a PC to get the cycle rate, you won't be able to get the duty cycle this way, but you can get frequencies greater than 10Hz easy with the soundcard.
Ya, the diode kills the ringing at the expense of dumping some of the energy in system. But the ringing usually occurs too long after triggering to be of much use anyway, as you say, it usually just causes suck-back. Since coil guns have incredibly crappy efficiencies anyway, dumping a bit of the energy in the diode really isn't that big a deal.
ACDCMONKEY: The RadioShack part number for the proper set of precut, preformed, proper gauge wires for the breadboard is in my earlier post. It is worth the money.