AIzaSyCh6hUF0tMKUn0HeUYUrp3Tq2tGwciCgM4

Counters are specially designed synchronous sequential circuits, in which , the state of the counter is equal to the count held in the circuit by the flip flops. Counters calculate or note down the number that how many times an event occurred.
http://www.rreowtech.com/counter/