Pulse Generator 1

123

00:56:58

-> Q2 is normally held in saturation by R_3, so it's output is close to ground (R_3 was chosen small enough to ensure Q2's saturation

-> When circuit's input is at ground, Q1 us cut off, with its collector at 5V

-> The capacitor is therefore charged, with 5V on its left terminal and appx 0.6V on it's right terminal. Cap has about 4.4V across it

-> A positive 5V input step brings Q1 into saturation, forcing its collector to ground

-> because of the voltage across the capacitor, this brings the base of Q2 momentarily to negative

published 2 years ago

skymero

2 years ago

the base is supposed to go to -4.4 momentarily, Q2 is then cut off and no cuurent flows through Q2s collector so its output jumps to 5V.. however I don't understand why this isn't doing that. What am I doing wrong here?

DrWhofromGallifrey

1 year ago

Try setting your pulse generator to 90 microseconds. Horowitz and Hill alluded to the RC value.

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