Date: 18 Jul 2013

Counter is a sequential circuit that runs through a sequence of states upon the given input pulses. The input pulses are called counter pulses. These pulses may be clock pulses or originate from an external source and may occur at specific intervals of time or at random. The sequence of states may follow a binary count or any other sequence of states.

Applications of counters

Counters are used in almost all equipments containing digital logic. Counters are used for counting the number of occurrences of an event and for generating timing sequences to control operations in a digital system.

There are three major applications: counting, frequency division and frequency measurement.

Counting: Counter is used to count the number of occurrences of particular events. The events are represented by count pulses. For example, a counter can be used to count number of consecutive failed login attempts. It can also be used to control a sequence of operations.

Frequency division: A binary counter can be used as a frequency divider. For example, it can generate one count pulse per second in a digital clock. For this purpose, flip-flops are used.

Frequency Measurement: Counter is used to measure the unknown frequency of a periodic signal. During sampling interval, it receives the pulses of unknown frequency and starts counting.