Applied to two variables, a and b, is represented as S = A·B = A and B. The following table and image correspond to this function:

A B S = A·B 0 0 0 0 1 0 1 0 2 1 0 0 3 1 1 1

The demonstration is that when ...

a)      the current flows when both are closed;

b)      corresponds to the representation of AND gate according to norm DIN;

c)       according to norm ASA. The electric circuit is the association of two switches in a row.

In this case, the builders also create integrated circuits with TTL or MOS technology with two entries (7408).