Question

7-

a) What components determine the frequency of an astable, 555 oscillator? Draw the circuit.

b) Draw a circuit for both an astable and a monostable, 555 multivibrator.

c) What is the duty cycle and percentage duty cycle of a pulse train or square wave?

d) What is the overshoot, rise time, fall time, and pulse width of a pulse and where on the waveform is each measured?

Answer 1

a) ASTABLE 555 timer -

Capacitor(C1) and both resistor(R1 and R2) determine the frequency of an astable multivibrator

b) MONOSTABLE 555 Timer

c) Duty cycle of square wave for astable multivibrator is given by

  

For square wave duty cycle is 0.5 or 50%

d) Overshoot : It is defined as the occurance of any signal exceeding its target values.

Rise Time : It is the time taken by the signal to change from 10% to 90% value.

Fall Ime: It is the time taken by the signal to change from 90% to 10% value.

Pulse width: It is time taken during which the waveform is energised.