# ANSI four-input NAND gate

Canonical URL: https://eloragrid.ai/symbols/ansi-four-input-nand-gate
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: NAND4
Drawing use: Schematic
Reference families: IEEE / ANSI, Manufacturer

## Symbol convention

Convention: IEEE / ANSI
Form: D-shaped AND outline with four inputs and an output bubble
Distinctive-shape form as used in IEEE/ANSI-style schematics and manufacturer data books. Independent educational drawing; exact standard geometry and compliance are not asserted. The counterpart is the matching functional concept; no equivalence of every detailed standard graphic is asserted.
Related representation: [NAND gate](https://eloragrid.ai/symbols/logic-nand-gate)

Four-input D-shaped NAND gate with an output bubble; its output goes low only when all four inputs are high.

## In plain English

### What does ANSI four-input NAND gate mean?

A four-input NAND gate is drawn with the AND outline, four input leads and a bubble at the output. The output is low only when every input is high. The function is supplied by dual four-input NAND packages and is a common building block for address decoding and multi-condition alarms.

### A simple example

Where some inputs are active low in the design intent, the drawing may show the same device in its De Morgan form as an OR outline with bubbled inputs. Either representation is valid, but the chosen form should match the meaning of the signals so that the sheet reads naturally.

### What the drawings help you do

The symbol alone does not show which package or gate section is used. Reference designators and pin numbers come from the device schedule.

### This particular reference

Four-input D-shaped NAND gate with an output bubble; its output goes low only when all four inputs are high. An OR outline with bubbled inputs is the De Morgan equivalent of the same NAND function.

### 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.

- [SNx4HC20 dual 4-input NAND gates](https://www.ti.com/lit/ds/symlink/sn74hc20.pdf)


## What it represents

A four-input NAND gate is drawn with the AND outline, four input leads and a bubble at the output. The output is low only when every input is high. The function is supplied by dual four-input NAND packages and is a common building block for address decoding and multi-condition alarms.
Where some inputs are active low in the design intent, the drawing may show the same device in its De Morgan form as an OR outline with bubbled inputs. Either representation is valid, but the chosen form should match the meaning of the signals so that the sheet reads naturally.
The symbol alone does not show which package or gate section is used. Reference designators and pin numbers come from the device schedule.

## How to read it

- Check for the output bubble; without it the gate is an AND.
- Consider whether an equivalent OR form is used elsewhere for the same device.

## Information to show or reference

- Draw four evenly spaced inputs.
- Mark the output bubble clearly.
- Add the gate section and pin numbers when used for wiring.

## Important distinction

An OR outline with bubbled inputs is the De Morgan equivalent of the same NAND function.

## Facts

- Inputs: Four
- Output low when: All inputs high
- Artwork scope: Original educational illustration; consult the applicable standard and the selected device documentation for the exact graphic

## Public references

- [SNx4HC20 dual 4-input NAND gates](https://www.ti.com/lit/ds/symlink/sn74hc20.pdf) — Texas Instruments. Manufacturer documentation for dual four-input NAND gates.

## 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.