Hardware Categories


Logic Gates
Computers and digital component use binary 0 and 1, where 0 is low voltage (0 volts) and 1 is high voltage (+5 volts). Binary information is carried by signals and manipulation of binary information is done by logic circuits called as gates.
A circuit whose input and output signals are two states on and off. A gate is logic circuit with one or more input signals but only one output signal.
Basic types of Gates :
AND Gate
 Two or more input signals and one output signal.
 Output is high when both the inputs are high.
 Logic equation Y = A . B called as Boolean equation.
 Where A and B are the inputs and Y is the output for all standard symbols of gates shown below.
OR Gate
 Two or more input signals and one output signal.
 Output is low when both the inputs are low.
 Logic equation Y = A + B.
NOT Gate
 One input signal and one output signal, also called as inverter.
 Output is always opposite state of the input.
 Logic equation Y = A
 Where is A is the complement of A.
NAND (Not AND) Gate
 Two or more input signals and one out signal.
 It has high output when at least one of the input is zero or low.
 All input signals must be high to obtain low output.
 Logic equation Y = A . B
NOR (Not OR) Gate
 One or more input signals and one output signal.
 If one of the input is high then output is low
 Logic equation Y = A + B
XOR (Exclusive OR)Gate
 Two or more input signal and one output signal.
 Output is low when both the inputs are same.
 Logic equation Y = A XOR B
XNOR (Exclusive NOR) Gate
 Two or more input signal and one output signal.
 Is combination of XOR gate followed by invertor.
 Output is high when both the inputs are same.
 Logic equation Y = A XOR B


Tip Box
Logic gates are the basic components of all electronic components, without them electronic system can't be run.

