Logic probe simulation error

Discussion in 'Homework Help' started by Nayanesh Jirasinha, Jul 19, 2016.

  1. Nayanesh Jirasinha

    Thread Starter New Member

    Jan 8, 2016
    Hey guys i am currently working on a logic probe for an assignment and i am using the following circuit.
    I have simulated the circuit using Multisim but an error message keeps popping up.
    I have attached the reference circuit and the Simulated circuit.
    Can someone go through it and let me know if I've done any error in connecting the components?

    Your help is much appreciated.
    Thank you.
  2. absf

    Senior Member

    Dec 29, 2010
    I sim your circuit on proteus and it seems to work just fine. May be multisim doesn't like 7404 outputs being connected together. Try replace 7404 with 7405 (open collector inverter) with a 1K pull-up on pin #12 of 7405 (refering to your schematic) .

    logic probe.PNG