# IEC shift register (SRGm)

Canonical URL: https://eloragrid.ai/symbols/iec-shift-register
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: SRG8
Drawing use: Schematic
Reference families: IEC, Manufacturer

## Symbol convention

Convention: IEC
Form: Rectangular element with SRGm qualifier and a shift-right clock
Qualifying-symbol and dependency conventions as explained in TI's public overview of IEEE Std 91-1984, which incorporates IEC 617-12 work. Independent educational drawing; not certified IEC geometry or an IEC database identifier. The counterpart is the matching functional concept; no equivalence of every detailed standard graphic is asserted.
Related representation: [Serial-in parallel-out register](https://eloragrid.ai/symbols/serial-in-parallel-out-register)

IEC register marked SRGm with m stages; the clock carries the shift arrow and moves data one place each cycle.

## In plain English

### What does IEC shift register (SRGm) mean?

SRGm identifies a shift register of m bits. The clock input is labelled with C1 and a shift arrow, showing that each active edge moves data one place. The serial input is labelled 1D, and the parallel outputs are listed down the right side, typically in a column of per-bit elements under a common-control block.

### A simple example

On drawings, shift registers expand outputs for indicators or relay drivers, or capture serial data from a sensor. The reader should identify the shift direction, the serial input, and any output latch or enable, as these decide how and when outputs update.

### What the drawings help you do

The symbol does not show the data rate or the serial protocol. Those come from the controller documentation driving the register.

### This particular reference

IEC register marked SRGm with m stages; the clock carries the shift arrow and moves data one place each cycle. A latched shift register adds a storage register and its own clock between the shift stages and the outputs.

### Terms

- Coil: A wound conductor that can produce a magnetic field when energised.
- Signal: Electrical information passed between devices, rather than necessarily the main power supply.
- Schematic: A drawing showing function and connections rather than physical appearance.

Concept diagram: Identify the device and form → Read the connections and state → Check the equipment reference
A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.

- [Overview of IEEE Standard 91-1984: explanation of logic symbols (SDYZ001A)](https://www.ti.com/lit/ml/sdyz001a/sdyz001a.pdf)
- [SN74HC164 — serial-in parallel-out shift storage](https://www.ti.com/lit/ds/symlink/sn74hc164.pdf)


## What it represents

SRGm identifies a shift register of m bits. The clock input is labelled with C1 and a shift arrow, showing that each active edge moves data one place. The serial input is labelled 1D, and the parallel outputs are listed down the right side, typically in a column of per-bit elements under a common-control block.
On drawings, shift registers expand outputs for indicators or relay drivers, or capture serial data from a sensor. The reader should identify the shift direction, the serial input, and any output latch or enable, as these decide how and when outputs update.
The symbol does not show the data rate or the serial protocol. Those come from the controller documentation driving the register.

## How to read it

- Identify the shift direction from the arrow.
- Check for an output latch that holds outputs during shifting.

## Information to show or reference

- State the bit count in the qualifier.
- Label the serial input as 1D.
- Show the output latch and enable if present.

## Important distinction

A latched shift register adds a storage register and its own clock between the shift stages and the outputs.

## Facts

- Qualifier: SRGm
- Clock label: C1 with shift arrow
- Artwork scope: Original educational illustration; consult the applicable standard and the selected device documentation for the exact graphic

## Public references

- [Overview of IEEE Standard 91-1984: explanation of logic symbols (SDYZ001A)](https://www.ti.com/lit/ml/sdyz001a/sdyz001a.pdf) — Texas Instruments. Lists SRGm and shift right or left input labels.
- [SN74HC164 — serial-in parallel-out shift storage](https://www.ti.com/lit/ds/symlink/sn74hc164.pdf) — Texas Instruments. Serial-in parallel-out shift register documentation.

## Graphic scope

Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.