• A logic gate is an physical device implementing a boolean function, it performs a logical operation on one (or) more binary inputs and produce a single binary output.
  • These gates are implemented by using diodes (or) transistors acting as electronic switches, in practice these are implemented by using CMOS technology, FETs, MOSFETs.
  • These are used in multiplexers, registers, ALU's, and computer memory.
  • There are seven basic logic gates:
     1.AND
     2.OR
     3.NAND
     4.NOR
     5.XOR
     6.XNOR
     7.NOT
     1.AND GATE:
  • It is a basic logic gate that implements logical operations on (or) more binary inputs and produce a single binary output.
  • It behaves according to the
  • Truth table:

  • Symbol:   
  • AND gate by using NOR gate
                                    
  • AND gate by using NAND gate
                                     Image result for or gate by using nand gate
     2.OR GATE:
  • OR gate is a basic logic gate that implements logical operations on one (or) more inputs and produce a single output.
  • It behaves according to the 
  • Truth table:
  • Symbol:
            
  • OR gate by using NOR gate
  • OR gate by using NAND gate 
       
     3.NAND GATE:
  • It is a Universal  logic gate that implements logical operations on (or) more binary inputs and produce a single binary output.
  • By using this gate we can design any logic gate.
  • It behaves according to the 
  • Truth table:


  • Symbol:

     4.NOR GATE:
  • It is a Universal  logic gate that implements logical operations on (or) more binary inputs and produce a single binary output.
  • By using this gate we can design any logic gate.
  • It behaves according to the 
  • Truth table:
            Image result for nOR gate by using or gate
  • Symbol:
   Image result for nOR gate by using or gate
      5.XOR GATE:

  • XOR gate is a basic logic gate that implements logical operations on one (or) more inputs and produce a single output.
  •  An XOR gate implements an exclusive or; that is, a true output results if one, and only one, of the inputs to the gate is true. If both inputs are false (0/LOW) or both are true, a false output results.
  • It is a  inequality function, i.e., the output is true if the inputs are not alike otherwise the output is false.
  • It behaves according to the
  • Truth table:


  • Symbol:

  • XOR by using NAND gate
             
  • XOR by using NOR gate
     6. XNOR GATE:
  • XNOR gate is a basic logic gate that implements logical operations on one (or) more inputs and produce a single output.
  • It's function is the logical complement of the exclusive OR (XOR) gate.
  • XNOR gate is  called an "equivalence gate".
  • A high output (1) results if both of the inputs to the gate are the same. If one but not both inputs are high (1), a low output (0) results
  • It behaves according to the
  •  Truth table:
                       
    • Symbol:


    • XNOR by using NOR gate


         7.NOT GATE:

    • NOT gate is a logic gate which implements logical negation.
    • It is also called as inverter gate
    • It behaves according to the 
    • Truth table:
    • Symbol:

    • NOT by using NOR gate: