Astabil multivibrator

121

02:05:45

Astabili oscilaror. Anybody having an idea, why the multivibrator does behave a bit randomly? The width of the pulses is not exactly the same each time, sometimes switches to some weird status etc...? The scheme was taken from Wikipedia, values of resistors/capacitors are guessed. Btw shake your mobile phone to start osillations! 

published 10 years ago

Sine_eyed

10 years ago

Well, that was a pretty good guess on the component values. It should work well- I'm not sure why wiki would have you add the fifth resistor though. That 1M ohm really screws things up imo. Try this: start up the circuit and when it begins to oscillate wind the clock back up to real time and observe the scope. Then stop the circuit (press pause, move any one component a space to the side [doesn't matter which one] then press the "back" arrow at the far right of the toolbar- this will reset the circuit), then highlight that big resistor, on the toolbar click the scissors to disconnect it from the circuit. Press play, watch for oscillation again and check out the scope. Describe what you see..

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