ASYMMETRICAL_PULSE_GENERATOR

Published:2009/7/15 4:20:00 Author:Jessie | From:SeekIC

Charge and discharge paths of timing capacitor C1 in LM3900 IC connected as astable oscillator are individually controlled by D1 and D2. Value of R1a controls charge rate of C1 and period t1, while R1b controls discharge rate and period t2. Resistors can be pots for providing variable pulse width and repetition rate. For constant frequency with variable duty cycle, R1 can be single pot with ends going to D1 and D2 and tap going to output. For values shown, t1 is 1 ms and t2 is 4 ms.-W. G. Jung, IC Op-Amp Cook-book, Howard W. Sams, Indianapolis, IN, 1974, p 505.



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