Elenco Understanding Logic Gates - Manual (Page 12)

U19
NOR Gate
NOR gates are used in digital logic circuits to perform an inverted logical add. When one of the inputs is
high (1), the output is low. The output will only be high (1) when both inputs are low.
A
Q
B
1
1
1
1
1
2
2 2 2
2
2
2
0
Input (A) Input (B) Output (Q)
0 0 1
0 1 0
1 0 0
1 1 0
This circuit demonstrates how the NOR Gate
(U19) works. Connect one end of the red and
black jumper wires to the A & B inputs on U19
and the loose ends to either low voltage (denoted
as a “0”) or high voltage (denoted as a “1”). If,
and only if, both input A AND input B are low (0,
both green LEDs are off), then the Q output on
U19 will be high (1), and the red LED (D1) will be
on. The output logic is exactly the opposite of the
OR gate, hence this gate is called the
NOT OR or
NOR Gate