[sdiy] what are these?

[Roy J. Tellason]

On Saturday 23 October 2004 05:37 pm, Roy J. Tellason wrote:
> I'm still sorting through parts...
>
> In this small bag labeled "optoisolators" I find these five things.  About
> an inch long more or less,  mayba a cm wide,  and irregular in contour --
> there are two wires coming out of each end,  and the rest is covered by a
> layer of heatshrink.  Markings are "SIGMA 932" and "301T1-PC" and "26148". 
> I'm not measuring anything with an ohmmeter between pairs of wires...
>
> Reminds me a little bit of those units that Fender used to use for
> "vibrato" except that these were obviously mounted on some board or other, 
> wires are fairly short and all pointed in the same direction.
>
> Any of you guys have any ideas about these?

Ok,  I opened one up,  since there only seemed to be 3 rather than 4 leads 
coming out of it.  And what do I find?  Another layer of heatshrink,  this 
one thin and yellow.  I can see what looks like the tip of a neon bulb 
peeking out of one end of the shrink,  and this yellow stuff is apparently 
transmissive enough that this time when I put the meter across the photocell 
I get readings that drop down to close to 100 ohms as I get closer to the 
lamp over my desk.

Regular optos I can find a use for (and I have some,  and plans for them),  
but not ones driven by a neon bulb.  Any of you guys have a use for these?