Digital Electronics

Logic gates are the basic building block of digital circuit. As Digital circuits only understands 0 or 1.The logic Gates are too build upon to operate on 0s and 1s. In most cases 0V is 0 and +5V represents the 1 value.There are seven basic logic gates-
 1.AND : It works like a logical ‘AND’ operator. You can say the gate multiplies true (1) and false (0)

value. Output is 1 only when both the inputs are true.

2.OR  : It is like a inclusive OR operator in logic operation. It outputs true when any of input or both

inputs are true.

3.XOR : It is exclusive OR operator. Output true only if one of inputs are true but not both.

4.NOT: NOT Gate performs as not means. Output is the complement of input.

5.NAND: It outputs the complement of AND gate.

6.NOR: It is Not OR means The result of OR gate is complemented here.

7.XNOR: It outputs true if both the inputs are in same state i.e. either both are ‘true’ or both are ‘false’.

Seven Basic Gates

Universal gates are those which can be used for implementing any of the other gates. NAND and NOR gates are the universal gates.
Logic gates operates only on true and false value.It takes more or less rules from Boolean algebra.Some of important rules from Boolean expression which come handy are-

• Commutative rule: A+B=B+A , AB=BA
• Associative rule : A+(B+C)=(A+B)+C, A.(B.C)=(A.B).C
• Distributive rule: A.(B+C)=AB+AC, (A+B).C=AC+BC, A+BC=(A+B).(A+C)
• Identity rule: A+A=A, A.A=A
• Boolean postulates: A+0=A, A+1=1, A.0=0, A.1=A, A'+A=1, A'.A=0
• Negation rule: (A')'=A
• Absorption rule: A+A.B=A, A.(A+B)=A
• DeMorgan's rule: (A+B)'=A'.B', (AB)'=A'+B'

Circuits are designed with the above said basically.Majority gate is a digital circuit whose output is one if its majority in the inputs are 1.Two Level network is a network where there is at most two intermediate gates.There can also be three or many more level network.

Boolean Expressions(SOP and POS forms)

Truth Table

Karnaugh's Map

Combinational Circut

Sequential Circuit

Number System