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inversion bubble

inversion bubble.svg
The symbol for an inverter is that of a buffer with an inversion bubble at the output.

The inversion bubble is a schematic symbol that's used in conjunction with logic gates that indicates the signal at that point is inverted. Inversion bubbles can be found on inputs, outputs, or both.

DeMorgan's Law[edit]

Main article: DeMorgan's Law

As a consequence of DeMorgan's Law, one can often move the inversion bubble around in order to optimize a circuit. The ability to generate equivalent networks is very important in naturally inverting technologies such as CMOS because it eliminates redundant inversions.

nand gate using negated inputs.svg = nand gate (ansi).svg
nor gate using negated inputs.svg = nor gate (ansi).svg

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