Take a look at the circuit diagram. Now you have four flip-flops in the chain, with the output Q of the forward flip-flops directly connected to the D input of the following flip-fops. In addition, all flip-flops are connected directly to the clock signal (Clk) and switch synchronously.
Circuit diagram of a 4-bit shift register. |
At each clock signal (Clk), the stored values are "pushed" to a flip-flop to the right.
In this case, a new value is stored in Q3, while the last value (Q0) is "pushed" out of the shift register.
Circuit of a 4-bit shift register. (Enlarge) |
You can extend this chain almost indefinitely. In fact, shift registers of several thousand flip-flops were used in mainframe computers in the 1970s.
In the next experiment you take a look at the, for shift register, important RESET input...
