Astable Multivibrator using NE 555 timer IC

Posted on Feb 5, 2014

Astable Multivibrator can be designed by using 555 timer IC, Op Amps and also using transistors. The 555 IC provide accurate time delay from mille seconds to hours. The frequency of oscillation can be controlled manually by simple modification. This is a simple 555 timer circuit project. Astable Multivibrator is simply an oscillator circuit that pr

Astable Multivibrator using NE 555 timer IC
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oduces continuous pulses. The frequency can be controlled by changing the values of R1, R2 and C1. When the capacitor voltage less than 1/3 Vcc, the lower comparator output will be high, then the control flip flop get set to High. (Q=1, Q`=0, Final output=1). 4th pin is Reset pin, a Low voltage at this pin resets the IC. The Low signal is applied to the base terminal of reset transistor Q2. Then it turns ON followed by Discharge capacitor Q1 and capacitor discharges. See the images below.

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