DIGITAL LOGIC - NOR GATE

1.11 DIGITAL LOGIC - NOR GATE

The NOR gate is a standard OR gate with the output inverted. The NOR gate is a logic 1 output only if all other inputs are 0. Under any other condition the output is always 0. The notation used to express this logic statement is C = A+B and is read "C equals A OR B NOT".

 Function

The function of a NOR gate is similar to the circuit shown below. Only if A and B have no input and therefore their relays not energized is the relay K3 not energized. With relay K3 not energized, the switch is closed and there is an output at C.

 Truth Table

The various combinations of inputs and the resulting outputs for the function circuit are shown below.

 Timing Diagram

The timing diagram shows the resulting output at C with inputs at A and B at different times for the circuit shown below.

Figure :Digital logic – NOR GATE