# IEC buffer element (rectangular form)

Canonical URL: https://eloragrid.ai/symbols/iec-buffer
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: 1
Drawing use: Schematic
Reference families: IEC, Manufacturer

## Symbol convention

Convention: IEC
Form: Single-input element marked 1 without negation
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: [Non-inverting logic buffer](https://eloragrid.ai/symbols/logic-buffer)

Non-inverting IEC element marked 1, passing the input state to the output unchanged.

## In plain English

### What does IEC buffer element (rectangular form) mean?

A rectangular element with the additional drawing mark 1 and no negation simply repeats its input. It is used to show isolation between logic stages, a fan-out point, or an interface where a physical buffer device exists. When the buffer has greater than normal drive capability, an amplifier triangle pointing in the signal direction is added inside the outline.

### A simple example

On logic diagrams for control panels the buffer often marks where a signal leaves one card or module and enters another. Tagging the buffer with the module reference helps fault finding because it identifies the boundary at which the signal can be measured.

### What the drawings help you do

A plain 1 element says nothing about output type or enable. Three-state, open-collector and Schmitt variants each require an additional additional drawing mark.

### This particular reference

Non-inverting IEC element marked 1, passing the input state to the output unchanged. The same box with output negation is an inverter; the amplifier triangle inside marks increased drive capability.

### Terms

- Normally open / normally closed: The contact state in the normal condition defined for the drawing.
- 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)
- [SN74LS07 — open-collector output buffers](https://www.ti.com/lit/ds/symlink/sn74ls07.pdf)


## What it represents

A rectangular element with the qualifier 1 and no negation simply repeats its input. It is used to show isolation between logic stages, a fan-out point, or an interface where a physical buffer device exists. When the buffer has greater than normal drive capability, an amplifier triangle pointing in the signal direction is added inside the outline.
On logic diagrams for control panels the buffer often marks where a signal leaves one card or module and enters another. Tagging the buffer with the module reference helps fault finding because it identifies the boundary at which the signal can be measured.
A plain 1 element says nothing about output type or enable. Three-state, open-collector and Schmitt variants each require an additional qualifier.

## How to read it

- A buffer may exist only to show a module boundary; check the module tag.
- Look for drive, three-state or open-circuit qualifiers next to the output.

## Information to show or reference

- Mark the element with 1.
- Add the output qualifier where the output is not a normal push-pull stage.
- Identify the physical device or module when one exists.

## Important distinction

The same box with output negation is an inverter; the amplifier triangle inside marks increased drive capability.

## Facts

- Qualifier: 1
- Optional additions: Amplifier triangle, three-state, open-circuit, hysteresis
- 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. Defines 1 and the increased-output-capability triangle.
- [SN74LS07 — open-collector output buffers](https://www.ti.com/lit/ds/symlink/sn74ls07.pdf) — Texas Instruments. Manufacturer buffer 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.