XOR Gate Definition
The XOR gate is a type of derived logic gate used in digital
electronic circuits to perform exclusive OR operation. It is a two-input and
one-output logic gate. XOR gate is also called Exclusive OR Gate, or Ex-OR Gate, or X-OR Gate.
The XOR gate produces a HIGH (Logic 1) output only when its two
inputs are in different logic states, i.e. the output of the XOR gate will be
HIGH, when its two inputs are 0 and 1 or 1 and 0. When the two inputs of the
XOR gate are the same, it produces a LOW (Logic 0) output.
The XOR logic gate is also known as an anti-coincidence gate or
inequity detector because it gives output 1 only when its inputs are not
equal or coincide.
The output of the XOR gate is obtained by performing the modulo
sum of its two inputs.
It is called Exclusive OR gate because it gives in output
equal to Logic 1, only when exclusively one of its inputs is a Logic 1.
It is important to note about the XOR gate that three or
more input XOR gates do not exist. When we require an XOR gate with inputs of more
than two, then multiple two-input XOR gates are connected together to obtain
the desired XOR gate.
XOR Gate Symbol
The logic symbol of the two-input XOR gate is shown in the
following figure.
Here, A and B are inputs and Y is the output of the XOR gate.
XOR Gate Truth Table
The truth table of the XOR gate is given below:
|
Inputs |
Output |
|
|
A |
B |
Y |
|
0 |
0 |
0 |
|
0 |
1 |
1 |
|
1 |
0 |
1 |
|
1 |
1 |
0 |
From the truth table of the XOR gate, it is clear that the
output of the XOR gate is logic 1, only when its two inputs are different,
and for the same inputs, it gives a logic 0 output.
XOR Gate Boolean Expression
The Boolean expression or logical function of the XOR gate
is given below.
The output of the XOR gate is obtained by
performing the modulo sum of its two inputs.
XOR Gate Switching Circuit
The following figure depicts the
switching circuit of the XOR gate.
It has two switches A and B, a battery, and a lamp.
From the circuit diagram, it can be seen
that when the two switches are at different logic levels, i.e. A = 0 and B = 1
or A = 1 and B = 0, then the circuit completes and the lamp is turned on.
When the two switches are at the same
logic level, i.e. A = B = 1 or A = B = 0, the circuit remains open and the lamp
remains turned off.
This is how the above switching circuit
implements the XOR logical operation.
XOR Gate IC
The IC 7486 is a commonly available quad 2-input XOR gate IC used in various digital electronic systems. It contains four XOR gates in a single IC chip.
The following figure shows the pin
diagram of the 7486 XOR Gate IC.
Applications of XOR Gate
The XOR gate is commonly used to
implement various digital electronic circuits and systems. Some common digital
circuits are listed here that use an XOR gate as their component.
- Half-adder and full-adder circuits
- Sequence detector and corrector circuit
- Binary subtractors
- Pseudo-random number generator
Hence, in this article, we have discussed
all the important aspects of the XOR gate (Exclusive OR gate).
Other Useful Resources
You can get more knowledge about XOR gate from the following resources.
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