The basic building blocks of a computer are called logical gates or just gates.

Gates are basic circuits that have at least one (and usually more) input and exactly one output. Input and output values are the logical values true and false. In computer architecture it is common to use 0 for false and 1 for true. Gates have no memory. The value of the output depends only on the current value of the inputs. This fact makes it possible to use a truth table to fully describe the behavior of a gate.

We usually consider three basic kinds of gates, and-gates, or-gates, and not-gates (or inverters).