The diagram shows four flip-flops connected to form a SERIAL IN, SERIAL OUT shift register.
to its Q
output. At the start, the contents of the register can be set to zero by means of the CLEAR line.
If a 1 is applied to the input of the first flip-flop, then upon the arrival of the first clock pulse, this 1 is transferred to the output of flip-flop 1 (input of flip-flop 2).
After four clock pulses this 1 will be at the output of flip-flop 4. In this manner, a four bit number can be stored in the register.