Registers are binary storage elements that consist of flip-flops and gates. They belong to the family of sequential circuits. The registers are referred as clocked sequential circuits when the combinational circuits are absent. Registers are used to load and store binary information when the clock pulse of the flip-flop circuit is enabled.
The flip-flops in a register can either be JK or D flip-flops. The number of flip-flops used in a register depends on the bits to be stored. If two bits are to be stored then two flip-flops are used. Thus, each flip-flop is capable of storing only single bit. Though the flip-flop stores the data, it is the logic gate that determines the manner in which the data is transferred into the register.