LOGIC GATES

Seven digital-logic symbols — and how to build six of them from a single element, NAND

Built as a memo rather than a table: the thing worth hanging it up for reads across the room, with the full reference in smaller type below it.

Three sizes in one archive — from a sheet on the fridge to a poster on the wall.

Formats: A4 · A3 · A2
What you get: Print-ready PDFs, one per size, with every letterform converted to outlines — nothing to install, nothing to shift.
Subject: code · school · memo · classroom

Read each symbol by shape: a flat back with a curved front is AND, a pointed shield is OR, a triangle with a circle is negation. A bubble on any symbol’s output means the same thing — negate the result.

NAND IS THE ONLY ELEMENT YOU NEED

From NAND alone you can build an inverter, AND, OR, NOR, XOR and XNOR — a digital circuit needs no other element: INVERTER — 1, AND — 2, OR — 3, NOR — 4, XOR — 4, XNOR — 5 NAND elements.

That is why 7400-series chips are mass-produced from one repeated element instead of seven different ones — NAND, not AND or OR, is the one that most digital logic is actually built from.

On the sheet

Read each symbol by shape: a flat back with a curved front is AND, a pointed shield is OR, a triangle with a circle is negation. A bubble on any symbol’s output means the same thing — negate the result.
Colour carries meaning, but meaning never rests on colour alone — the sheet reads in black and white.
Nothing about how it was made: the sheet carries only what the reader needs.

Printing

Three sizes in the archive: A4 — 210×297 mm, A3 — 297×420 mm, A2 — 420×594 mm.
All text is converted to outlines. No fonts to install, and nothing shifts on another machine.
White background and sparing fills — it prints on a home printer without draining the cartridge.
Margins of at least 10 mm: a home printer cannot print to the edge.
No stroke thinner than 0.3 mm, so nothing disappears in print.

Why the numbers can be trusted. Every countable number here is computed from data rather than typed in, and the sheet must pass 9 independent checks before it is allowed to build — how many items there are, the order they come in, and the claim in the highlighted box itself. If one fails, there is no file.

LOGIC GATES

NAND IS THE ONLY ELEMENT YOU NEED

On the sheet

Printing

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