Single pulse on the scope, no oscillator, and you can actually see the shape of the pulse and use the time scale of the oscilloscope to determine the pulse duration. The problem is triggering the scope. You might trigger it with the same camera contact used to trigger the flash, that is probably the easiest thing. You also get to see the delay of the flash.
On Saturday 11 December 2004 17:14, D. Glenn Arthur Jr. wrote: FJW> William Robb wrote: FJW> > From: "Kevin Waterson" FJW> > Subject: flash duration FJW> > FJW> > > Is it possible to measure the duration of a flash? FJW> > > Possibly in micorseconds or something? FJW> > FJW> > I think you need an oscilloscope for that. FJW> FJW> That was my first thought -- a phototransistor and a FJW> sillyscope. (Sorry, couldn't resist.) But since FJW> the oscilloscope's already been mentioned, I started FJW> wondering how else to do it ... what about an oscillator, FJW> a counter, and a phototransistor? With a 1 MHz FJW> oscillator, and the phototransistor between that and FJW> the counter, whatever the counter counts up to is the FJW> duration of the flash in microseconds ... FJW> FJW> But not having significant EE-fu, I must second-guess FJW> myself and ask whether I'm correct in assuming that FJW> a phototransistor responds quickly enough for this...? FJW> FJW> (If not, then whatever thyristor (photo-SCR??) they FJW> use in flash units that have a sensor ought to be FJW> fast enough.) FJW> FJW> -- Glenn FJW> FJW> FJW> -- Frits WÃthrich
