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peterkat2's picture



peterkat2joined February 20, 2017

posted Friday, March 3, 2017 | 3:44 am PST

I made this design, it is public and called Amv Test, you can find it and test it.

it is to see how it works with two blinking LEDs, but it does not oscillate

I changed some values of the components so that there is a difference between the left and right side but it does not work.

Do I do something wrong or does SystemVision not understand the schematic

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Astable Multivibrator Does Not Oscillate

Your schematic looks correct although I didn't try to run too many of the numbers. It looks like the transient solution remains at the DC operating point. You might try replacing the battery with a pulsed source that steps from 0 to 12V at t=0. This will let the transient solution try to find an operating point with the caps active. The DC solution is found with open circuits in place of the caps. This results in identical states for both transistors. The caps are included in the transient solution and there should be no stable operating point.

If that doesn't work you might try unbalancing the two legs of the multivibrator at t=0. In real life oscillations are started by noise voltages. A voltage pulse at t=0 in series with either base might replicate this noise.