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Two inputs simultaneously

Discussion in 'General Electronics Discussion' started by oscarbastos, Aug 25, 2014.

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  1. oscarbastos

    oscarbastos

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    Aug 25, 2014
    [​IMG]
    How can i connect a led to output 1 and 2 and it only power on when the 2 inputs are pressed simultaneously?
     
  2. Arouse1973

    Arouse1973 Adam

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    Dec 18, 2013
    Um and what is the device you are using? Might be helpful to know that first.
    Adam
     
  3. oscarbastos

    oscarbastos

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    Aug 25, 2014
  4. Arouse1973

    Arouse1973 Adam

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    You could use an AND gate on the output. You can use a logic gate or make it from a two transistors. Do you really need two LEDs? One LED will tell you the output is on.
    Adam
     
  5. oscarbastos

    oscarbastos

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    Aug 25, 2014
    yes i want to connect the 2 outputs to only one led, how can i make it from 2 transistors?
     
  6. Arouse1973

    Arouse1973 Adam

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    Dec 18, 2013
    Here you go.
    AND.png
    Adam
     
  7. BobK

    BobK

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    Jan 5, 2010
    Assuming the outputs are capable of driving and LED, you can do it with one transistor:

    and.JPG
     
  8. Arouse1973

    Arouse1973 Adam

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    Dec 18, 2013
    Smarty pants :)
     
  9. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    Or you can save one resistor by using the transistor as an emitter follower and connecting the collector to one output and the base to the other, with the LED and current limiting resistor between the emitter and 0V. (Need to reduce the resistor to compensate for the base-emitter voltage drop). Bam! He shoots, he scores :)

    Edit: Oops! Foul ball! That circuit would put a diode junction between the two outputs. BobK, I concede defeat :)
     
  10. Arouse1973

    Arouse1973 Adam

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    I removed one doped piece of N type silicon and one resistor :)
    TOUCH_SENSE.JPG
     
    Last edited: Aug 26, 2014
    KrisBlueNZ likes this.
  11. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    Nice one Adam! If a bit of wasted current is not a problem, that's a nice solution!
     
    Arouse1973 likes this.
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