jumbo Posted March 6, 2006 Report Share Posted March 6, 2006 Hi allI am trying to build a basic phototransistor circuit.Objective: to sense small variations of light and translate them to a voltage variation.I have seen many circuits on the internet, and none shows where the base is connected to?? already got a phototransistor, and it got 3 pins (B-C-E), so where should i connect the base to??Plus, does any of you have a nice circuit that can be useful to me? Because it is the first time i deal with phototransistors...Any help would be apreciated...NB: please keep in mind that im trying to build a sensor that can detect SMALL variations of light...Thank you. Quote Link to comment Share on other sites More sharing options...
Tony_Stoynov Posted March 7, 2006 Report Share Posted March 7, 2006 Hi,yes in the internet has a many circuite diagram, you can look at www.national.com ot wwwintersil.com, and also www.analog.com, in this website you can see different aplication notes.You must have a minde that phototransistor is more sensitive, compared with a photodiode, and is a very easy to saturate it. Base yuo can leave not connected, but with the base you can compensate some problem with saturation, and with a noise. Quote Link to comment Share on other sites More sharing options...
Staigen Posted March 7, 2006 Report Share Posted March 7, 2006 Hey, didn't I made a posting to this topic, why have that been removed? Hey, moderators, why?//Staigen Quote Link to comment Share on other sites More sharing options...
audioguru Posted March 7, 2006 Report Share Posted March 7, 2006 Hey, didn't I made a posting to this topic, why have that been removed? Hey, moderators, why?//StaigenHi Staigen,Your post wasn't deleted. Jumbo posted his question on 3 different forums here and you and I are answering him on different forums. I think the moderators should combine all posts that are the same. While they are at it, the moderators should get rid of the guy who is selling his pcbs on our forums. Quote Link to comment Share on other sites More sharing options...
steven Posted April 20, 2006 Report Share Posted April 20, 2006 :)look in the forums somewhere fairchild photo transistor data, it inclkudes 2 circuits that sense light, i used Quote Link to comment Share on other sites More sharing options...
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