Logic Gates & Truth Tables Flashcards

All 8 cards in this deck

What is a logic gate?

A circuit component that takes one or more inputs and produces a single output based on a logical function.

When does an AND gate output 1?

Only when both of its inputs are 1; otherwise the output is 0.

True or false? An OR gate outputs 0 when both of its inputs are 1.

False. An OR gate outputs 1 when at least one input is 1, including when both are 1.

What does a NOT gate do to its input?

It inverts it: an input of 0 gives output 1, and an input of 1 gives output 0.

What is a truth table?

A table that lists the output for every possible combination of inputs to a gate or circuit.

In a truth table, what do 1 and 0 represent?

1 represents TRUE and 0 represents FALSE (they may also be written as T and F).

How many rows of input combinations does a truth table need for a circuit with $n$ inputs?

$2^n$, e.g. 2 inputs need 4 rows and 3 inputs need 8 rows.

When does an XOR gate output 1?

When exactly one of its inputs is 1 (the inputs are different). It outputs 0 when both inputs are 0 or both are 1.