# IEC common-output element

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

## Symbol convention

Convention: IEC
Form: Element below an array with a double line at its top, carrying a general qualifier
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.

Element with a double top line that produces one output depending on all elements of an array above it.

## In plain English

### What does IEC common-output element mean?

TI's public overview of IEEE Std 91 describes the common-output element as having a double line at its top. It sits beneath an array of identical elements and produces a single output that depends on all of them, such as a combined carry or an all-equal flag. It must carry its own general additional drawing mark to say what function it performs.

### A simple example

On data-book style drawings the common-output element saves repeating a gate for every bit. When reading it, look at the additional drawing mark in the element (for example & or ≥1) and remember that its inputs come from each element above as well as any external inputs drawn on its side.

### What the drawings help you do

The double line only signals the structural role. Without the additional drawing mark inside, the function is undefined, and the drawing should not be accepted in that state.

### This particular reference

Element with a double top line that produces one output depending on all elements of an array above it. The common-control block has a notched outline at the top of an array and distributes inputs downwards; the common-output element collects results at the bottom.

### Terms

- 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)


## What it represents

TI's public overview of IEEE Std 91 describes the common-output element as having a double line at its top. It sits beneath an array of identical elements and produces a single output that depends on all of them, such as a combined carry or an all-equal flag. It must carry its own general qualifier to say what function it performs.
On data-book style drawings the common-output element saves repeating a gate for every bit. When reading it, look at the qualifier in the element (for example & or ≥1) and remember that its inputs come from each element above as well as any external inputs drawn on its side.
The double line only signals the structural role. Without the qualifier inside, the function is undefined, and the drawing should not be accepted in that state.

## How to read it

- Look for the qualifier inside the double-line element; it defines the function.
- Inputs come from every element in the array above.

## Information to show or reference

- Draw the double line clearly at the top of the element.
- Include a general qualifier.
- Show any additional external inputs on the side.

## Important distinction

The common-control block has a notched outline at the top of an array and distributes inputs downwards; the common-output element collects results at the bottom.

## Facts

- Distinctive feature: Double line at the top edge
- Requirement: Must carry a general qualifier
- 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. Describes the common-output element and its double-line feature.

## 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.