Hi all,
How do i connect a 3 legged photo transistor? L14G3
And what does the lens on top of it do?
Check out L14G1 pdf, L14G1 Description, L14G1 Datasheet, L14G1 view ::: ALLDATASHEET :::
If I remember my transistor theory correctly, a phototransistor only requires two legs -- a collector and an emitter, because the light that enters the phototransistor's lens serves as the base that switches the output signal.
I believe (someone correct me if I'm wrong) that when the base is provided on a phototransistor than the base can be used to switch the transistor in the dark...
well it has 3 pins.. base, emitter and collector... now i presume i take an analog input from the collector, base to ground and emitter to supply. Is this right?
"well it has 3 pins.. base, emitter and collector... now i presume i take an analog input from the collector, base to ground and emitter to supply. Is this right?"
I belive that is right. However there should be a load resistor from the collector to Vcc voltage, and the analog input is taken from the junction of the resistor and collector. The base pin can be used to set the bias for the phototransistor such that the transistor is operating in a linear mode, otherwise it may just act like a simple switch, showing light or no light. Should be lots of circuit examples on the web and different phototransistors will most likely have different bias requirements depending on how you want to utilize it.
Thanks Lefty
I found more info here that may help the OP:
http://encyclobeamia.solarbotics.net/articles/phototransistor.html
Bill Thanks for checking it out. I appreciate it. I had checked it out and the datasheet before putting my question here. Unfortunately i'm from a non-electronics / non-science background and trying to learn things by experimenting. Now i was looking for someone to simplfy all that for me :-[ anyways i think i'm going 1 step back and looking at normal transistors..