Digital System, Switch, boolean algebra

Digital
systems

Definition:

A
digital system deals with quantities or variables which have only two discrete
value states.

Examples of Quantities:

i) A
switch can be either open or closed

ii) The answer of a question can be either yes or no

iii) A certain statement can be either true or false

iv) A bulb can be either off or on

These
states are also called logic states or
logic variables 

Boolean
algebra:

Boolean algebra also known as algebra of
logics. It is a branch of mathematics which deals with the relationships of
logic variables.

 Instead of variables that represent numerical
quantities as in conventional algebra, Boolean algebra handles variables that
represent two types of logic propositions; 'true' and 'false’

The algebra used to describe logic
operations by symbols is called Boolean Algebra. Like
ordinary algebra, English alphabets (A, B, C, etc.) are

used to represent the Boolean variables. However, Boolean variable can have
only two values; 0 and 1.

LOGIC
Operations

Digital circuits perform the binary
arithmetic operations with binary digits ‘1’ and ‘0’. These operations are
called logic function or logical operations

There are three universal operations.All
other operations are the combination of these three operations.

i) AND operation

ii) OR operation

iii) NOT operation