Question

write a short note on digital counters, what is the major difference between counters and registers? what are the major applications

Answer 1

Counter is a device which stores(and displays) the number of times a particular event or process has occurred, often in a clock signal. It is a sequential circuit used for counting pulses. Counter is the wildest application of flip-flops. Counters are constructed using flip- flops (flip-flops are bi-state devices, which means they have two states, either zero(0) or one(1)).

Although any flip-flop can be suitably connected to form a counter, most widely used are D and JK flip-flops.

A single flip-flop can track a count of two i.e. it counts from 0 to 1 and hence called mod-2 counter. On the same grounds, one can expect two flip-flops connected in series to form 2-bit counter ccounting from 0 to 3 comprising of 4 states and hence can be referred to as mod-4 counter. Generalising, one gets n-bit or mod-n counter of (2ⁿ-1) by cascading n flip-flops. To behave as a counter, flip-flops must be driven by high (logic-state 1) at their inputs, both in D as well as JK types.

Difference between register and Counter - Registers are combinations of flip-flops for storing more than one bit of information.A register is a set of flip-flops with combinational logic to implement state transitions that allow information to be stored and retrieved from them.

Counters are special type of registers.A Counter is simpl a register with combinational logic to implement counting, that is possible to retrieve the contents, add or subtract one to the contents, and then store it back into the register in open operation.

Both Registers and Counters are composed of flip-flops. The basic difference is that the Registers do not follow a specific sequence of states unless very specialized application. Whereas, Counters always follow a specific sequence of states, they are bound to follow a sequence.

Applications- Counters are used in Alarm Clocks, to set time in camera to take a picture, common use in home appliances like microwave(time schedule LED indicator), washing machine, digital clocks, also used in digital to analog converters,