Transistor doesn`t work?

Discussion in 'The Projects Forum' started by Vaarna, Nov 17, 2015.

  1. Vaarna

    Thread Starter New Member

    Nov 17, 2015
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    I have a simple circuit with 2 transistors making an and gate and switches to turn on the transistors and a led to light up when the 2 switches are on, but
    it doesnt work the transistors just heat up.

    ps.sorry if i`m noob
     
  2. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    post a schematic..... noob :p

    A schematic will show all the details your words left out.
     
  3. GopherT

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    Nov 23, 2012
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    Post a close-up photo of your circuit and a hand drawn (or better) schematic of the circuit. Also include the value of the resistors you used.
     
  4. Vaarna

    Thread Starter New Member

    Nov 17, 2015
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  5. GopherT

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    Your transistors have been damaged because you should have a resistor between the (+) and base of the transistor. Look at the datasheet for the transistor and look up the max current into the base.
     
  6. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    Yes you have omitted the resistors to the Bases of the transistors, so they will burn up, use any values from 1K to 10K.
     
  7. GopherT

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  8. GopherT

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  9. mcgyvr

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    Don't even need the transistors just put the 2 switches in series.. (or are the switches momentary..even so)
     
    Last edited: Nov 24, 2015
  10. GopherT

    AAC Fanatic!

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    I think he is experimenting - making an AND logic gate.
     
  11. Vaarna

    Thread Starter New Member

    Nov 17, 2015
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    yes its a "prototype"
     
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