AVR-Chat

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>> In the end, this SSR is a kick-ass optocoupler.
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>At $5.00 each it better be !

They do tend to be pricey.

I did a fun circuit once, with a dual-optoisolator, and an opamp, to implement a modem hybrid without any transformer, and full isolation to the phone line. 

Within limits, it works pretty well.  The audio goes through the opamp, driving current into both LEDs, with the opamp's feedback taken from one output transistor. The other transistor is sitting in the phone line circuit.  If Q1 is passing 5mA, then Q2 is usually pretty darned close, in a dual opto, since they are made at the same time.  You have to be careful that they are a dual chip, and not two single dies in a dual package though, as the matching then is back to the 10/1 sort of range.