Digital Logic Toolkit

Digital Logic Toolkit — Buffer

Source
https://digitallogictoolkit.com/buffer-gate/
Printed

Open-collector buffer driving an LED — buffer gate

edge casethe interface use

Answer

LED = 1

Why this example is worth doing

A buffer sized to sink far more current than an ordinary gate, used to drive an LED, a relay or a long cable. Logically it is still the identity function. The page includes it to close the argument the whole page has been making: a component's value can lie entirely outside its logic function, and a course that only ever looks at truth tables will find the buffer inexplicable.

Try your own input in the Buffer. Truth table, symbol and algebraic form for the non-inverting buffer, and what it is for.

How the answer is reached

The probed row

A = 1

Output table

Output table — columns A, LED
ALED
00
11

Compare with

Open the Buffer

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