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From: firstname.lastname@example.org (Gregory L. Hansen)
Subject: Re: Camera Flashes
Date: Sat, 30 Nov 2002 14:04:32 +0000 (UTC)
Organization: Indiana University, Bloomington
References: <email@example.com> <firstname.lastname@example.org>
NNTP-Posting-Date: Sat, 30 Nov 2002 14:04:32 +0000 (UTC)
X-Newsreader: trn 4.0-test62 (21 February 1998)
In article <email@example.com>,
John Muchow wrote:
>>>>Well, all the camera will see is a nine volt battery feeding the gates of
>Perfect. And very similar to what I did with a similar circuit a few
>years ago. I had to parallel up to twelve 2400WS Speedotron flash
>packs and they all had high-voltage, high-current sync circuits that
>were frying the sync circuits of a couple of cameras. I ended up
>using a 9V battery and a MOC3023 with a R/C network on the input that
>pulsed the triac when the camera fired. The flash sync circuits
>dropped to zero volts when fired so the sync stayed "ON" (shorted
>through the triac) plenty long enough to work for just about any flash
>unit out there, and turned off by itself when the sync voltage dropped
>far enough. And I didn't need a 555 to create a pulse.
Uh-oh. Are there some timing issues here? I think my circuit was going
to be a lot simpler than yours; when the camera sync is on the FETs are
on, when the camera sync goes off the FETs turn off because the battery
would be disconnected and the gate charges drain through a resistor, I
was thinking 10K. Battery in series with the camera's sync port, to a
bunch of FET gates in parallel, then to ground through a resistor.
Plus a "test" button, and a battery check button that would fail to light
an LED under conditions I haven't really decided yet, but connected to a
voltage divider that would fail to generate enough voltage to turn on the
LED when the battery is weak enough.
"A nice adaptation of conditions will make almost any hypothesis agree
with the phenomena. This will please the imagination but does not advance
our knowledge." -- J. Black, 1803.
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