Description
The IC 555 timer was invented by “Signetic Corporation” and it was termed as SE or NE555 timer. Generally, it is a monolithic timing circuit that gives precise and highly stable delays of time or oscillation. These types of ICs are very cheap and reliable in cost when we compared with the OP-Amp applications in the same areas. These ICs are used as an astable and monostable multivibrators in digital logic probes, DC-DC converters, tachometers, analog frequency meters, voltage regulators, temperature controlled and measurement devices. The IC SE555 is used for where the temperature ranges from – 55°C to 125°C and the IC NE555 is used for where the temperature ranges from 0° to 70°C
 
Features of the 555 Timer
555 timer IC works from a wide range of power supplies ranging from +5V to +18V.
Sourcing or sinking load current is 200mA.
The external components must be selected correctly, so that the timing intervals can be completed in several minutes along with the frequencies beyond several hundred kHz.
The o/p of a 555 timer IC can drive TTl due to its high current o/p.
It takes a temperature stability of 50 ppm/oC change in temperature (ppm means parts per million)
The timer’s duty cycle is adjustable.
The max power dissipation per package is 600 milliwatts & its reset and trigger i/ps has logic compatibility