Understanding pnp transistors

105

01:28:25

Can anyone explain to me why current flows initially but once you press the push button to turn on the led, the current no longer flows again unless the button is pressed?

published 6 months ago

ViolationMad

6 months ago

If you add a trace to the base of the transistor and increase the timescale a bit, you can see it slowly converging towards 10V. It seems like the DC opt.- point calculation during simulation startup straps the base to ~9.6V theough the BC/BE junction capacities. As soon as the BE junction depletes, the current stops (more precisely at -100pA Ice).

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