On 8/18/2010 8:01 PM, Jim Nichols wrote:
> Hi Chuck,
>
> How would one go about measuring the circuit voltage? Could I place a meter
> across the contacts at the base of the unit
Yes. With the flash turned on and fully charged, that will measure the trigger
voltage.
> and trigger it manually?
Nope, no need to trigger it at all. You are measuring the voltage across the
contacts or solid state device that trigger
the flash by shorting that voltage out briefly.
In early flashes, those contacts completed the circuit that dumped the flash
capacitor voltage through the flash tube,
so the voltage could be a few hundred volts. It was the switch that turned on a
light, in effect.
Later designs used semiconductor devices to act as the switch for the full
flash voltage. That not only allowed
relatively low voltages (and currents) across the camera sync contacts, but
made possible auto flashes. An additional
circuit used a photocell to determine when to turn the electronic switch off
again.
> It has a trigger button on the side of the flash. Or, does the meter have
> to be in the actual camera-to-flash circuit when the camera triggers the
> flash?
Heavens no.
Dr. No Flash
--
_________________________________________________________________
Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
Archives: http://lists.thomasclausen.net/mailman/private/olympus/
Themed Olympus Photo Exhibition: http://www.tope.nl/
|