I have some type of solarcell-diode ,it looks like a 5mm led (it's not I've tried) when hooking this thing to a multimeter set for resistance unlike a photoresistor or phototransistor this thing will read 1m forward and 0 with leads reversed more like a solar panel I'm thinking I've answered my own question (what is this thing?) but nowhere can I find a solarcell in a 5mm led type pkg. Any clues identifying this part would be awsome.
Connect the short lead to 5 to 9v.
Connect the long lead to a 10k to 100k resistor
Connect the other end of resistor to ground.
- Measure voltage across the resistor,
- cover the device to exclude light, measure again
- Shine light on it and measure again.
(Make sure you are focusing light right into it from an LED flashlight).
If voltage changes, it is either a photodiode or an IR LED.
Now, connect the short leg of device to 0V, long leg to a 1k resistor and the other end of resistor to 5 to 9v
Measure voltage across Device. If 0.7 to 2volts, and no light is coming off of it, it is an IR LED.
If some color light can be seen when looking at the the flat surface, it is a standard LED (and voltage across the device will likely be 1.8 to 3.5v