# Why doesn't this ring oscillator work in LTspice?

EDIT_1 :

• I replaced 2 capacitors that were 22F instead of 22 μF and updated the images.
• I stopped the simulation at t = 19.5μs as you can see on the image below because it is very slow, uses a lot of storage and the voltages values seem to already point to a problem.

I'm trying to learn how a ring oscillator works by simulating it using LTspice. But the various plots don't seem to be correct. Below are two images showing the schematic and the plots.

I found the original schematic here

Does anyone know what the problem is ?

Thanks

• What is the time constant of a 22Farad capacitor and a 10000 ohm resistor? And how long did you simulate? Dec 16 '20 at 19:23
• Try changing one of the resistor values slightly to ensure that one of the transistors gets turned on before the others. For example, change R1 to 9.95k. Dec 16 '20 at 19:25
• You changed the simulation to run for 300 ms, but your chart only shows the first 16 us. What happened for the next 284 us? Dec 16 '20 at 20:20

• @helenp R7 does absolutely nothing since it's across a(n ideal) voltage source. You also have no ground that I can see in your picture. Dec 17 '20 at 8:22