Shift register
cascade of flip-flops sharing the same clock, in which the output of each flip-flop is connected to the input of the next flip-flop in the chain, resulting in a circuit that shifts by one position the bit array stored in it
A shift register is a type of digital circuit using a cascade of flip-flops where the output of one flip-flop is connected to the input of the next. They share a single clock signal, which causes the data stored in the system to shift from one location to the next. By connecting the last flip-flop back to the first, the data can cycle within the shifters for extended periods, and in this configuration they were used as computer memory, displacing delay-line memory systems in the late 1960s and early 1970s.
In most cases, several parallel shift registers would be used to build a larger memory pool known as a "bit array". Data was stored into the array and read back out in parallel, often as a computer word, while each bit was stored serially in the shift registers. There is an inherent trade-off in the design of bit arrays; putting more flip-flops in a row allows a single shifter to store more bits, but requires more clock cycles to push the data through all of the shifters before the data can be read back out again.
Shift registers can have both parallel and serial inputs and outputs. These are often configured as "serial-in, parallel-out" (SIPO) or as "parallel-in, serial-out" (PISO). There are also types that have both serial and parallel input and types with serial and parallel output. There are also "bidirectional" shift registers, which allow shifting in both directions: L → R or R → L. The serial input and serial output of a shift register are connected to create a circular shift register.
The public source identifies “Shift register” as cascade of flip-flops sharing the same clock, in which the output of each flip-flop is connected to the input of the next flip-flop in the chain, resulting in a circuit that shifts by one position the bit array stored in it. This brief keeps that definition visible, then builds a research path around Shift, register and cascade.
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Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated Jul 20, 2026. The linked authority identifier is Q746165. The Library of Congress control number is sh85121409. 1 of 1 selected statements include explicit references; 1 carry qualifiers and 0 use preferred rank.
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This entry incorporates text from “Shift register” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.