What is an atomic clock?

Atomic clock is a special type clock that shows almost accurate time. Atomic clock maintains continuous and stable time scale. the first model of atomic clock was build on 1949 by the U.S National Bureau of standards. First successful atomic clock was designed on 1955 in UK by National physical laboratory. A chip scale atomic clock designed in august 2004 by NIST scientists. Chip type atomic clock consumes only 75 mw current. Major application of atomic clocks are to generate standard frequency and serve time signals to time signal sites. They also installed at navigation transmitters and broadcasting stations. By the help of this atomic clock signals broadcasting stations produces accurate carries frequency. GPS navigation systems base signals are also from atomic clock.