Multisim Convergence Issue

Discussion in 'Electronics Resources' started by dmarciano, Jun 25, 2011.

  1. dmarciano

    Thread Starter Member

    Oct 10, 2007
    Online I found a continuity tester circuit that I was planning on implementing into a project I'm working on. I built the circuit on a breadboard and it worked. So I decided to simulate it in Nation Instrument's Multisim so I can test it with the other parts of the project. However when I try to simulate it the LEDs don't light and I get a convergence issue (Timestep too small). I let the convergence assistance run to try and resolve the issue, however it failed to do so. I've a attached an image of the circuit directly from Multsim, and I was hoping someone could help explain how I could get it to work.

    Please not that in the circuit I added switch S2 and resistor R9. The circuit to be tested for continuity would be connected between R1 & R3 to between R3 & R4. I added the switch so I could simulate adding and remove the circuit and I added R9 with a value of 2Ohms because the original circuit said to test it with a resistor between .22Ohms and 4Ohms.
  2. cirkits

    New Member

    Jul 6, 2011
    Hi there,

    Add ground (GND) to your circuit and see if that makes a difference. Any simulation in Multisim requires at least one power supply and ground.


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