OK fine folks, here's the dilemma: I'm making a sound trigger that fires a camera. A timer is used to turn the trigger circuit on at the appropriate time. The alarm output from the timer is connected to the gate of an SCR which, when activated, closes the sound trigger circuit. The circuit can also be turned on by a toggle switch which bypasses the SCR. Now, when the circuit is activated by the timer/SCR, it is less sensitive. Circuit voltage measures about .9V less than when the bypass switch is used to turn on the circuit. So I'm losing .9V through the SCR and losing sensitivity. Is there a fix for this? Possibly, an SCR with different specs might be the remedy, but I can't decipher the specs (as posted on the Mouser web site.)
Help: SCR voltage drop
Jun 19, 2006
3 Replies
SCRs do indeed have a typical forward voltage like the one you measured.
Do you need to use an SCR ?
Graham
The SCR is the simplest solution I know of. But I think the voltage drop is moot. With an old battery the sensitivity was low, but with a fresh batt, the slight drop in voltage (and therefore, sensitivity) is negligible. So I guess I'm okay.
Thanks Graham,
Greg
you can probably use a transistor or a 555 timer + transistor instead of that scr. Why don't you post a scheme or URL, so we can give better advice
ciao Ban
Apricale, Italy
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