Optocoupler

Like a lot of numbers..

from what I can see it is a 4 pin device ? and if so, the pins 1 and 2 are the input LED or LED's, if could be an AC type? to test that, you can use the diode test and it should test the same both ways as a LED diode.

The output looks like a NPN transistor. Collector is on 4 and emitter on 3.

But, maybe I have it incorrect..

JAmie

On Tue, 22 Jan 2013 23:42:25 +0100, Fred Bartoli put finger to keyboard and composed:

Manufacturer/Proponent: OPTEK INC

Optek part number search turned up nothing:

FWIW, the following discussion suggests that KT3172 crosses to HP part

- Franc Zabkar

On Sun, 27 Jan 2013 19:32:44 +1100, Franc Zabkar put finger to keyboard and composed:

The service manual for the HP3457 may have some specs and circuits:

- Franc Zabkar

Not a Russki Pt No is it?!