[ic-racer]

I had forgotten, but it has come back to me now, that when the capacitors charge up, they are directly connected to the xenon tube. That is: there is no 'power switch' or relay to connect the voltage to the tube. Once the capacitor is charged, the xenon tube is also energized (so be carefull).So, at rest, the resistance across the electrodes inside the xenon tube is too high to allow any current to flow from the big capacitors.

So, how does it fire? There is a third wire to the xenon tube, and this wire leads to a coil (like a small automotive ignition coil) which leads to the ignition capacitor, described above (#4). When this circut is discharged it sends a pulse of current to the xenon tube which lowers the resistance in the tube, allowing the actual flash capacitor to discharge through the tube and make the bright light.

Some interesting things about the circut. The three 'flash speed' circuts are color coded, red, orange and green. The actual flash voltage travels THROUGH the little push button switches contancts. The wires carrying all that voltage are very small (I guess because the current is small or short duration)