The 555 timer is used to make time delays in electronic devices as an oscillator. It is an Integrated circuit (IC) chip that is easy to use in many timer applications. It is also used as pulse generator or oscillator. It is highly stable to produce accurate time delays in sensitive appliances. The derivatives provide up to four timing circuits in one package.
It was introduced in 1971 by Signetics Corporation. It was initially name as SE555/NE555. It helped in making user friendly circuits. It was normally called “The IC Time Machine. The IC is known particularly for its cheap rates as compared to other similar devices. The chip was later introduced in many devices and was widely manufactured by different companies. These days CMOS version of the IC is mainly used.
The nature of device is basically digital (specially the output) though the functioning relies on both analogue and digital techniques. A dual version of 555 timers is known as 556, in which two free 555 ICs are placed in a packed container.
The output produced by the device can either be low state or high state. In low state the voltage 0V and in high state the voltage of device is nearly equal to the supplied voltage. It ranges from 4.5 Volts to 18 Volts.