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What values to use to get phototransistor to respond only to lazer

Discussion in 'General Electronics Chat' started by mik3ca, Nov 28, 2017.

  1. Colin

    Colin Member

    Joined:
    Sep 25, 2003
    Messages:
    418
    Likes:
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    Location:
    Australia
    What you are saying is completely wrong. A photo transistor will work in both directions to a different extent and it is working in your circuit simply due to the enormous gain provided by the following transistor. But you are providing false information to the beginner and this has to be pointed out. Bringing in "red herrings" is not buffering your case. LEDs are completely different to a transistor.
    I have already stated that you only need the photo transistor and a load resistor.
     

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