An AND gate is the physical realization of logical multiplication (AND) operation. It is an electronic circuit that generates an output signal of 1, only if all input signals are also 1.
Fig 5.1 Two or more switches connected in series behave as an AND gate
Behaviour of a logic gate (the state of its output signal, depending on various combinations o of input signals) is represented conveniently by means of a truth table. Below Figure shows the truth table and block diagram symbol for an AND gate for two input signals. Since there are only two inputs (A and B), only four (2 2 ) combinations of inputs are possible. Notice that the output is 1 only when both inputs are in 1 state, otherwise it is 0.
Fig. 5.2 Block diagram symbol and truth table 5.4 foran AND gate.
