David,

Any chance we could see a schematic?

Joe

At 21:58 26/05/98 -0500, you wrote:
>
>I did this a while back, using a pair of optos, with the LEDs in series.
>The idea is that the photocurrent in the "B" transistor is the same as in
>the "A"
>transistor, since the LEDs have the same current. It is important to feed
>the
>LEDs with current, rather than voltage.  I expected it to be very finicky,
>but in
>fact it was easy, stable, and very repeatable.  No fancy pricey special
>optos.
>
>Four optos and a dual opamp, and I had a reasonable hybrid.
>
>