counter

Integrated circuit containing a digital counter (synchronous 4-bit decade counter, Signetics 74162N)

In digital electronics, a counter is a sequential logic circuit that counts and stores the number of positive or negative transitions of a clock signal. A counter typically consists of flip-flops, which store a value representing the current count, and in many cases, additional logic to effect particular counting sequences, qualify clocks and perform other functions. Each relevant clock transition causes the current count to increment or decrement (increase or decrease by one).