Re: Opto Coupler Help?

David Berlind

Yes. Thanks. I was just wondering if there was another trick, like the 9V
battery on the LED side, to check for the proper voltage drop on the
photocell side. For example, since the photocell is designed to impede A/C
signal, why not attach an SG across the photocell?

Thank you again

On Thu, Feb 22, 2018 at 1:44 PM, Harvey White <>

On Thu, 22 Feb 2018 13:09:50 -0500, you wrote:

@harvey, ok.. one detail I didn't include is that the photocells (the
resistor part of the OCs) are not in series. The LEDs are in series (on a
10 volt loop). But the photocell-sides are sprinkled into various parts
the clean and dirty circuits to restrict or permit the flow of signal.
are most definitely not in isolated series.

Then you'll get the resistance changed by whatever the parallel
connections happen to be. Still ought to tell you a bit.


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