Hi Beta and Tim!
As a very interested about electronic flash, I would like to take part at this issue and say some things about.
Before nothing Beta, the part you have found attached to the camera seems as it were only the "torch", containing the tube itself, the on-off switch and the reflector.
The missing part of the apparatus are the "generator" containing the whole power unit (storage battery, vibrator, step-up transformer, rectifier tube, main capacitor, power switching relay and triggering contactor). This latter piece, heavyly weighted, usually was fitted with a shoulder strap to be easily carried while taking pictures.
Both parts was linked by means of a multi-wire cable of usually four wires. Two of them for the on-off switch and the other two for tube powering.
Self-ionizing Amglo tubes was no needed of a third outside placed electrode for triggering because when the adequate voltage was applied to the main electrodes, the arc did strike between them due to the relative lower pressure of Xenon into the tube. These voltage from the main capacitor was applied by means of a rough relay controlled by the camera shutter's synchronization contacts.
Additionally the torch could contain a resistive voltage divider to drive a little neon pilot lamp that signals (when lit at near 100 volts) when the main capacitor's voltage are enough to strike the tube at the adequate power level to take a photo with correct exposure, depending on distance from subjet, lens aperture and film speed.
As Tim could say you, the voltage level for these tubes are slightly high, being around the 2 to 3 Kv DC.
Modern flash units (including most powerful two piece ones for reporter's use) does not exceed the 500 volts, and does use the called "Edgerton" triggering system, whose main characteristic are the three-electrode tube. Such tubes are fitted with the two main electrodes -anode and cathode- plus another third one outside placed. Usually this electrode are constituted by a simple wire helix surrounding the tube itself, or by a metal ring around one of the tube ends, near one (or both) of the main electrodes.
When the main capacitor are fully charged, a high voltage surge from a little induction coil or step-up transformer, are applied to the external electrode sincronically with the full shutter's opening, giving as a result the ionization of the Xenon into the tube and striking the main arc to discharge the condenser and give the flash.
I must say you I have a true and powerfull German "Multiblitz Press Universal", a two- piece (generator + torch) report flash from 60's (my favourite and actually in use) that works at 510 volts, but are transistorized and fitted with Edgerton system spiral tube.
About the tube reference you mention Beta, could be 5804X? (the same as you sent me, Tim)
Best regards,
M. Gonz?lez.
http://mis-bombillas.webcindario.com[This message has been edited by M?nico Gonz?lez (edited June 21, 2004).]
