A number of 555 astable example circuits are seen below. They are all based on the same circuit (DIA. A). The circuit continually resets itself and the LED flashes on and off until all power is removed. The circuit diagram shows that pins 6 and 2 are connected, this means that the circuit resets and triggers itself.

DIA 'A'

The bulb is turned on and off repeatedly. This cycle stops when the toggle switch is turned off.

Increasing the value of the resistors and capacitor extends the time the bulb is illuminated and the time it is off.

The LED is turned on and off repeatedly. This cycle stops when the toggle switch is turned off.

Increasing the value of the resistors and capacitor extends the time the LED is illuminated and the time it is off.

The motor is turned on and off repeatedly. This cycle stops when the toggle switch is turned off.

Increasing the value of the resistors and capacitor extends the time the motor is on and the time it is off.