Desparate for a Pinout for opto sensor

[bigal_scorpio]

Hi folks,

I really need a pin out for this opto sensor I have, it looks like the one in the picture except it has only one lug at the side, it is marked on top 1990 and 1142, and even after relentless googling I found nothing.

I can work out the anode and cathode ok but cannot tell which is the Collector or Emitter, because the transistor only has 2 connections

So if u can help me to find out I would be very greatful.

Thanks for looking...............Al

 

[KMoffett]

Just a guess but the pin outs may be pretty standard.
https://www.simplemotor.com/oimotor.htm
One thing to try is hook oyur ohmmeter across the C-E leads and turn the LED on (With an appropriate dropping resistor). If the resistance drops when the LED is on, the + lead of the meter is to the collector and - is the emitter. If nothing happens, reverse the leads and try again.

Ken

 

[on1aag]

Hi Bigal_scorpio,

The 1142 is the IR-LED and the 1990 is the phototransistor.
Take your multimeter and select diode test, measure across
the 1142 led, forward and reverse. Forward you should measure
about 1 volt, reverse should be open circuit.

Take a power supply and a current limiting resistor and give
the IR-LED about 10 mA, forward of course.
Take your multimeter and measure the 1990 side, forward and
reverse. Forward you should measure about 250 mV, reverse
again open circuit.

Any more questions before I put the damn thing back ?

on1aag.

 

[bigal_scorpio]

Thanks for the help guys - should be sorted now!

Cheers to you both, I'm getting my meter out now

Regards................Al