Digital Logic Toolkit

Digital Logic Toolkit — Logic gate symbols

Source
https://digitallogictoolkit.com/logic-gate-symbols/
Printed

Buffer — triangle with no bubble — logic gate symbols

exam standardthe gate that does nothing, and why it exists

Answer

output column 01

Why this example is worth doing

A buffer's truth table is the identity, which makes it look pointless until you add the enable input and get the three-state buffer — the part that lets many drivers share one bus. The page shows the enable line entering the top of the triangle and explains the third output state, high impedance, which is not a logic value and does not belong in a truth table as 0 or 1. That distinction between a logic level and an electrical state is worth drawing early.

Try your own input in the Logic gate symbols. Every gate in both symbol standards, side by side, on a printable one-page chart.

How the answer is reached

Truth table

Truth table — columns #, A, A
#AA
000
111

Compare with

Open the Logic gate symbols

This input is entered in the tool itself — it is too rich for a link to carry.

Note:

Notation this page assumes

  • Symbols: · is AND, + is OR, ⊕ is XOR, a prime or an overline is NOT. The field also takes ∧ ∨ ¬ ~ ! & | and the words.
  • Operator precedence, tightest first: NOT, then AND (including juxtaposition), then XOR/XNOR, then NAND/NOR, then OR, then IMPLIES, then IFF.
  • Gate symbols follow whichever standard the header toggle is set to: ANSI/IEEE Std 91-1984 distinctive shapes, or IEC 60617-12 rectangles.

Sources

  • ANSI/IEEE Std 91-1984, Graphic Symbols for Logic Functions
  • IEC 60617-12, Graphical Symbols for Diagrams — Binary Logic Elements