Astable Multivibrator Using Ic 555. Astable multivibrator using 555 ic is a simple oscillator circuit that generates continuous p. 14 traffic light circuit using 555 timer.
The ic 555 can be made to work as an astable multivibrator with the addition of three external components. It doesn t require a capacitor as the rc charging unit is not responsible for the generation of the output. These two resistors and the capacitor values are selected appropriately so as to obtain the desired on and off timings at the output terminal pin 3.
It has no stable states and continuously switches between the two states without application of any external trigger.
8th pin and 1st pin of the ic are used to give power vcc and gnd respectively. The 555 timer ic affords exact time delay from ms to hours. Astable multivibrator is also called as free running multivibrator. Above figure shows the circuit diagram of a 555 timer wired in astable mode.
