Digital circuits use transistors and integrated circuits to perform basic logic operations, which are modeled as logic gates for simplicity in design. Designers need only be concerned with the external logic properties of individual gates and not their internal electronics. Logic gates each perform a specific operation, with the output of one gate applied as input to others to form circuits, while Boolean algebra and truth tables provide the mathematical notation and specifications needed to analyze and design these binary logic systems.

1. Binary Logic and Gates
• Digital Circuits are hardware components that manipulate binary
information.
• The circuits are implemented using transistors and interconnections in
complex semiconductor devices called integrated circuits . Each basic
circuit is referred to as a logic gate. The term gate describe a circuit that
perform basic logic operation.
• For simplicity in design ,we model the transistor-based electronic circuits
as logic gate.
• Designer no need to be concerned with internal electronic of individual
gates but only with their external logic properties.
• Each gate performs a specific logical operation .output of
Gates are applied to the inputs of other gates to form logic circuit.

2. Boolean Algebra
• The Binary Logic system is one of a class of
mathematical systems referred to generally
as Boolean Algebra
• The name is in honor of the English
mathematician George Boole.
• It is necessary to introduce the mathematical
notation that specifies operation of each gate
and that can be used to analyze and design
circuits.

3. Truth Tables
• A truth table shows how a logic circuit's
output responds to various combinations of
the inputs, using logic 1 for true and logic 0 for
false.