phototransistor vs photointerruptor

Jun 10, 2004 1 Replies

What is the difference between these two items? I accidentally burned out one of these little units (the kind with the sensor and LED mounted right next to each other inside a small package) and went to digikey to replace it. I ordered a phototransistor from the catalog only to notice later that what I had use previously was *actually* a photointerruptor. (It came out of a CDROM drive head, paired with an optical encoder disc.) I noticed the difference because one package has a beveled corner and the other is totally square.



I suspect that a photointerruptor outputs discrete 0 or 5V logic levels, where as the phototransistor varies continuously. Correct? Please comment


|\/| /| |2 |< mehaase(at)sas(dot)upenn(dot)edu

A phototransistor is usually just a light detector (eg it needs a seperate light source).

A photointerrupter is usually a phototransistor or diode AND a light source/LED.

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