Bit of a wordy question title...
I was trying to simulate an astable multivibrator the other night and the simulation refused to run. I eventually realised that because the simulation assumes perfect components, therefore there is no way for the multivibrator to get going hence the failure.
So this means that the reason the astable multivibrator works as it does is only because of manufacturing defects/tolerances of the components used (You can use different values of resistors etc., but assuming identical components are used).
Which leads to the question, are there any other circuits out there which incorporate the manufacturing tolerances of components in their operation?
I've attached an image of an astable multivibrator. Whenever you look up any explanation, that explanation starts "Assume TR1 is OFF" or words to a similar effect.
Now I understand in the real world how this circuit starts and works, this question is not about that.
Assume that the circuit is initially powered up and all components are perfect and our traces have no resistance. This circuit would have no way to 'start'. Therefore, from this we can say this circuit only works they way it does because of imperfections that exist.
What my question is: Are there any other circuits which only function due to imperfections?