AND gate
Circuit Symbol:
A and B are inputs and Y is the output . It is a logic gate and hence A, B and Y can have the value of either 1 or 0 .
Boolean equation:
Y = A.B
It performs logical multiplication and is different from arithmetic multiplication.
Logic operation :
The output of AND gate is high (1) only when all the inputs are high (1). The rest of the cases the output is low . Hence the output of AND gate is high (1) only when all the inputs are high.
OR gate
Circuit Symbol:
A and B are inputs and Y is the output
Boolean equation :
A + B = Y
Logic operation :
The output of OR gate is high (logic 1 state) when either of the inputs or both are high.
NOT gate
Circuit Symbol:
A is the input and Y is the output.
Boolean equation :
`Y=bar(A)`
Logic operation :
The output is the complement of the input.
NAND gate
Circuit Symbol :
A and B are inputs and Y is the output.
Boolean equation :
`Y = bar(A.B)`
Logic operation :
The output Y equals the the complement of AND operation . The circuit is an AND gate followed by a NOT gate . The output is at logic zero only when all the inputs are high . The rest of the cases, the output is high (Logic 1 state.)
NOR gate
Circuit Symbol :
A and B are inputs and Y is the output .
Boolean equation :
`Y=bar(A+B)`
Logic operation :
Y equals the complement of OR operation (A OR B) . The circuit is an OR gate followed by a NOT gate and is summarized as NOR . The output is high when all the inputs are low. The output are low . The output is low for all other combinations of inputs.
Ex - OR gate
Circuit symbol :
A and B are inputs and Y is the output
Boolean equation: `Y=A.bar(B)+bar(A).B`
`Y = A oplusB`
Logic operation :
The output is high only when either of the two inputs is high . In the case of an Ex - OR gate with more than two inputs , the output will be high when odd number of inputs are high.
