Electronic – How to use this type of photodiode


I recently purchased the photodiode here and I am a bit confused on how to implement it. The reviews are all mixed on what is what, and the voltage for each is different so I am trying to be rather cautious so as to not burn one out. For some reason, it lists the photodiode as being the clear package and the tinted being the ir led, which seems strange to me. I have seen this post as well, and I am not sure of it as well. The diagram shows the cathode going directly to the 5v+, where I am used to putting a resistor before the diode. All I am trying to do is read whether it detects light or not with a microcontroller. How would I wire these? Oh, and the specifications listed on the website are different from those listed on the package. Any help is appreciated.

Best Answer

It's most probable that the clear package is the emitter.

It's very probable that the longests lead in each case is the Anode in both cases - ie the NON-bar end of the LED.

Photodiode are usually used in the reverse biased mode. eg like the circuit below from here

The reverse current of the diode varies with light level and is converted to a varying voltage by the opamp.

enter image description here AND HERE

The circuit below from here -> Gamma Photon Radiation detector is from Maxim Application Note 2236, and is used to detect Gamma Rays, aka Gamma Photons. This is done using a PIN duide whoch does not respond to visible light, but the principle is the same and as this is a low npise high performance circuit, the notes and the circuit itself give a good feel of what is needed to get best results.

enter image description here http://www.maxim-ic.com/images/appnotes/2236/2236Fig01.gif

A zilllion circuits from here and from here