LTSpice not simulating when using feedback loops

Discussion in 'General Electronics Chat' started by TheComet, Mar 11, 2013.

  1. TheComet

    Thread Starter Member

    Mar 11, 2013
    88
    12
    Hi,

    I'm trying to simulate a simple oscillator using a 74HC04.

    I successfully imported the model 74HC04 into LTSpice, but as soon as I connect it as shown below, LTSpice refuses to simulate it. I get some text at the bottom left saying "Stepping Source: blabla (Press ESC to quit)". If I press ESC a few times, the simulation output window will open, but it has only simulated 2ns, and shows no sign of motivation to continue.

    Here's the circuit:

    [​IMG]

    Attached is the project. I've included an "inverter import test.asc" which shows that the inverter is working, and the file "problem.asc" is the exact circuit seen in the picture above.

    Any help is appreciated,

    TheComet
     
  2. Jony130

    AAC Fanatic!

    Feb 17, 2009
    3,957
    1,097
    This circuit will not work. You need to use 74HC14 instead of 74HC04.
    Gate need a Schmitt trigger input to be able to work in this type of a circuit.
     
  3. Jony130

    AAC Fanatic!

    Feb 17, 2009
    3,957
    1,097
    I include my 74HC/ HCT and CD4000 lib
     
  4. TheComet

    Thread Starter Member

    Mar 11, 2013
    88
    12
    [​IMG]

    I feel stupid, thanks for the help! It now works perfectly.

    TheComet
     
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