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# What is the function of astable multivibrator in IC 555?

## What is the function of astable multivibrator in IC 555?

Astable multivibrator using 555 IC is a simple oscillator circuit that generates continuous pulses. The frequency of the circuit can be controlled by shifting the values of resistors R1, R2 ad capacitor C1.

## What is the function of control pin of 555 IC?

Control: Pin 5 is the control pin. In most 555 circuits, this pin is simply connected to ground, usually through a small 0.01 μF capacitor. (The purpose of the capacitor is to level out any fluctuations in the supply voltage that might affect the operation of the timer.)

What is the purpose of the diode placed in reverse in Pin No 3 of the 555 timer IC?

Resistor R1 limits current flow into the base of the switching transistor, and diode D3 is used in parallel with the motor to suppression and voltage transients as the motor is switched ON and OFF.

### How does a 555 timer work in astable mode?

At the beginning of an on/off cycle, the voltage is low at C1, the trigger pin, and the threshold pin. Whenever the trigger pin voltage is low, the output is on, and the discharge pin is off. Since the discharge pin is off, current can flow through resistors R1 and R2, charging capacitor C1.

### Which is the output pin of IC 555?

Pin-3
Pin-3 is the output pin of the 555 timer. We have connected an LED at the output pin in series with a 10KΩ resistor. This LED turns on when the pin-3 goes high.

What is astable operation?

The astable configuration generates an ongoing stream of pulses of fixed length and frequency. It’s called astable since it has no stable state, continually toggling back and forth.

#### Why is IC 555 called timer?

The 555 Timers name comes from the fact that there are three 5kΩ resistors connected together internally producing a voltage divider network between the supply voltage at pin 8 and ground at pin 1.

#### What is IC 555 Principle?

The working principle of the 555 timer is by considering the block diagram of the 555 timer IC. The first comparator has threshold input to pin 6 and control inputs for pin 5. Whenever the threshold voltage overcomes the control voltage then the first comparator is set to flip flop and the output is very high.

What is the three common operation mode of the IC 555?

The operating modes of a 555 timer are astable, bistable and monostable. Each mode of operation signifies with a circuit diagram and its output.

## What is the difference between monostable and astable?

Astable multivibrator, in which the circuit is not stable in either state —it continually switches from one state to the other. Monostable multivibrator, in which one of the states is stable, but the other state is unstable (transient). A trigger pulse causes the circuit to enter the unstable state.