Dumb ID question - LED vs. phototransistor

[crazydoc]

This is a Marktech (oops, I mean Vishay) CNY70 optoreflector. Unfortunately the package is symmetrical and leads are not marked. It is infrared so produces no visible light. I assume the device on the right is the LED as it pulls an appropriate current when forward biased, but just want to comfirm it visually, if someone can, before I solder it into the board. Thanks.

 

[CJ]

you still need to get the polarity right.
Do you have a voltmeter with a diode checker?
You should get infinite resistance one way, and about 1.5 volts drop the other way.

 

[gyraf]

The unit on the left looks like a photodiode, the one at right like a LED..

Jakob E.

 

[Steve Jones]

Most TV/video repair shops have a remote control tester which indicates when a remote is emitting IR radiation. If you have a friendly local repair shop they may lend you one for an hour or 2.

Otherwise put a piece of foil in front of it and hook a meter to the module and just trial and error it until you get a reading.

 

[gyraf]

Or - now that you obviously have a digital camera - simply point the camera at the LED, give the LED some 10mA, and you will be able to see the IR as blue light at the camera's monitor screen. This because most CCD sensor chips are very sensitive in the IR region, seeing IR as blue.

Check with a remote controller to make sure that your camera will react properly to IR.

Most (recent) video cameras works for this as well.

Jakob E.

 

[crazydoc]

Thanks y'all for your help. Yes, that on the right is the LED, at least by the diode tester. I'll try the camera method when I get it powered up. The one on the left is a phototransistor, at least by the spec sheet.