Due to historical reasons, digital circuits are called switching circuits, digital circuit functions are called switching functions and the algebra is called switching algebra. The algebraic system known as Boolean algebra named after the mathematician George Boole. George Boole Invented multi-valued discrete algebra (1854) and E. V. Huntington developed its postulates and theorems (1904). Historically, the theory of switching networks (or systems) is credited to Claude Shannon, who applied mathematical logic to describe relay circuits (1938). Relays are controlled electromechanical switches and they have been replaced by electronic controlled switches called logic gates. A special case of Boolean Algebra known as Switching Algebra is a useful mathematical model for describing the combinational circuits. In this section we will briefly discus how the Boolean algebra is applied to the design of digital systems.

Examples of Huntington 's postulates are given below:

Closure

If X and Y are in set (0, 1) then operations are also in set (0, 1)

Identity