Unidentified TO92 can PD/LD/??

[Samuel M. Goldwasser]

This is a TO92 can with 3 legs, 2 are isolated (the terminals
visible through the window).

Between the two isolated legs it measures as a diode with about a 1.52 V
forward drop on a DMM diode test. All other combinations test open on a
DMM. It does not appear to respond to visible light, at least not a 5 mW
green pointer watching the DMM voltage, but obviously either
detects or emits EM radiation of some sort due to the window. The voltage
drop dows change with temperature.

repairfaq.cis.upenn.edu/Misc/uid92-1.jpg
repairfaq.cis.upenn.edu/Misc/uid92-2.jpg

Thanks!

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[George Herold]

On Mar 25, 8:13 pm, s...@repairfaq.org (Samuel M. Goldwasser) wrote:
> This is a TO92 can with 3 legs, 2 are isolated (the terminals
> visible through the window).
>
> Between the two isolated legs it measures as a diode with about a 1.52 V
> forward drop on a DMM diode test.  All other combinations test open on a
> DMM.  It does not appear to respond to visible light, at least not a 5 mW
> green pointer watching the DMM voltage, but obviously either
> detects or emits EM radiation of some sort due to the window.  The voltage
> drop dows change with temperature.

An IR LD or LED? Have you tried pushing some current through it and
pointing it at some CCD camera?

I think 785 nm LDs have a forward voltage of about 1.5 Volts, I'll
check tomorrow.

George H.

[George Herold]

> > subject line.  Or, you can contact me via the Feedback Form in the FAQs.- Hide quoted text -
>
> - Show quoted text -

785 nm laser diode Vf (with Fluke 189 DMM) = 1.45 volts. Maybe you
have a bit shorter wavlength diode.

George H.

[johnci...@gmail.com]

Sam

Is there any possibility that it is some sort of ir sensor or pyrometer

I've seen them in to92 and to5 style cases
usually 1 lead for the case and 2 to the sensor.


John C

[Samuel M. Goldwasser]

I'm assuming some type of sensor. It is sensitive to temperature (voltage
drop changes) but not to visible light.

Before someone else suggested it, I did push a few mA through it in the
forward direction with no obvious effect except that that sample is now open.