Input voltage on output pin

Discussion in 'General Electronics Chat' started by Rocks45, Jul 18, 2017.

  1. Rocks45

    Thread Starter New Member

    Jul 12, 2017
    14
    0
    Here is a schematic of what iam trying to do.The Voltage sources are output pins on the IC and only one output pin will be pulled high at once.I believe the led will light up but will the IC have any damage or problems from connecting the 3 output pins together to the one led?or anything else to worry about?thanks

    http://tinyurl.com/ybr5egrr

    Outputs.jpg
    Mod edit: added local image from online schematic generator
     
    Last edited by a moderator: Jul 18, 2017
  2. JohnInTX

    Moderator

    Jun 26, 2012
    3,323
    1,667
    You don't say what IC it is. But since there is no pullup resistor, I assume that the IC output sources current to output 5V and sinks current for 0V outputs. In that case, you can't connect the outputs together as the low ones will short the high ones and cause problems.

    Consider a diode OR gate:
    [​IMG]
    https://en.wikipedia.org/wiki/OR_gate
     
    Last edited: Jul 18, 2017
    ebeowulf17 likes this.
  3. dhdavid

    New Member

    Jul 18, 2017
    2
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