Inverting gates


Martin McBride, 2017-01-04
Tags not gate nand gate nor gate truth table
Categories logic logic gates

There are two main types of inverting gates - NAND and NOR gates.

NAND gates

A NAND gate (NOT AND) is similar to an AND gate, but it produces the opposite output - if both inputs are 1, the output is 0, otherwise the output is 1.

This is the symbol for a NAND gate:

gate

You can think of the gate as being equivalent to an AND gate followed by a NOT gate:

gate

NAND Truth table

Here is the truth table for a NAND gate:

table

NAND interactive example

Here is an interactive NAND gate. Click on the inputs A and B to change their state, and see the output value Q.

NOR gates

A NOR gate (NOT OR) is similar to an OR gate, but it produces the opposite output - if either (or both) inputs are 1, the output is 0, otherwise the output is 1.

This is the symbol for a NOR gate:

gate

You can think of the gate as being equivalent to an OR gate followed by a NOT gate:

gate

NOR Truth table

Here is the truth table for a NOR gate:

table

NOR interactive example

Here is an interactive NOR gate. Click on the inputs A and B to change their state, and see the output value Q.

Video

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