Hello Russell,

> The "trick" in transferring analog signals via optos is either to
linearise
> the opto OR know its response curve OR (by far the easiest) use specially
> designed optos which have a single transmitter and two matched receivers
> which are both illuminated by the same transmit LED. One receiver is
placed
> in a  feedback loop on the sending side and a matching circuit is
> used by the other receiver on the receiving side. The "receiver-receiver"
> tracks the behaviour of the "transmit-receiver" and thereby replicates the
> input condition.

    maybe a linearizing table could be created on the microcontroller.
Probably the less expensive solution.

> To save explaining this and all its variants at length I'll cut to the
chase
> and suggest you look at the Siemens / Infineon IL300 as one example of a
> purpose built part. Infineon's app note 50 is a 17 page PDF that shows a
> number of ways of using the IL300. (I can send a copy offlist if you can't
> find it). While it is normal to use an opamp in the input circuit their
> simplest circuit requires two transistors on the input side and a single
> resistor on the output.

    Ok, Jinx already mentioned the TIL300. And I have no problems
undertanding it, but I'm thinking a transformer would be simpler.

    I'm trying to find the Infineon's AN50, but can't find where are the ANs
www.infineon.com. Please, send it to me off-list.

    Thank you very much,

    Brusque

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Edson Brusque                 C.I.Tronics Lighting Designers Ltda
Research and Development               Blumenau  -  SC  -  Brazil
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