Logic Gates

NOT Function

Inverts input, when input low output is high.

Express this function

X = A'

AND Function

Produces a HIGH output, when all inputs are high. Otherwise output is low.

Express this function

A*B, AB

OR Function

If all inputs are LOW, produces LOW output, otherwise output is HIGH.

Express this function

X= A+B

NAND Function

If all inputs are HIGH produces a LOW output, otherwise all outputs are HIGH

Express this function (NAND)

X= A’B’

NOR Function

Output is LOW until all inputs are LOW, then output is HIGH.

Express this function (NOR)

X=A’+B’

XOR Function

Output is LOW until both inputs are opposite logic levels, then input changes to HIGH

Express this function (XOR Gate)

X=A’B+AB’ ( Picutre of Circle Plus Sign)

XNOR Gate

Produces a HIGH input only when both inputs are the SAME logic level.

Express this function(XNOR )

X= (A’B+AB’)’

Fixed Logic Function

A type of logic function has a predetermined output for each combination of inputs and does not change

What are the 2 major Fixed Function Logic Families

TTL and CMOS