Elenco Understanding Logic Gates - Manual (Page 13)

U20
Exclusive OR (XOR) Gate
XOR gates are used in digital logic circuits to perform a comparison. When the inputs are mutually exclusive
(i.e. different), then the output is high (1). When the inputs are the same, then the output is low (0).
A
Q
B
1
1
1
1
1
2
2 2 2
2
2
2
0
This circuit demonstrates how the Exclusive
OR (XOR) Gate (U20) works. Connect one
end of the red and black jumper wires to the
A & B inputs on U20 and the loose ends to
either low voltage (denoted as a “0”) or high
voltage (denoted as a “1”). If input A and
input B are
exclusive (i.e. different, one
green LED is on and the other green LED is
off), then the Y output on U20 will be high
(1), and the red LED (D1) will be on.
Input (A) Input (B) Output (Q)
0 0 0
0 1 1
1 0 1
1 1 0