Posted on Oct 10, 2012 5080
The output-pulse width from the circuit is a linear function of the input pulse`s height. You can set the circuit`s input threshold to discriminate against low-level pulses, while fixed components limit the circuit`s maximum output -pulse width. With a 270-KO resistor connected from the -9 V supply to the base lead of Q2, this circuit can handle input pulses separated by 20 p.s for correct operation. The tum-off time of zener diode D2 sets the lower limit for the input-pulse repetition rate.
IC1, D1, and C3 detect the peak of the input pulse. The comparator IC2, triggers at your preset threshold. The RC del