Construction of XOR Gate Using Transistor

We can implement exclusive OR gate using transistor. Here is the circuit showing the connection of different circuit elements that are combined to implement the XOR operation.

Working of the Circuit

We will understand this circuit with the help of different scenarios of input in case of 2 input XOR gate:

CASE I: When both the inputs are zero. (A=0, B=0)

When both the inputs A and B are zero then transistors Q1,Q2,Q4 and Q5 are open circuit so the LED will not glow because both Q4 and Q5 are open so the negative pin of LED is not connected to the ground.

CASE II: When one input if logical high and other is logical low (A=1, B=0)

In this case we can easily see that Q4 is working as close circuit now. So the negative pin of the LED is connected to Q3 via Q4 and ultimately which is connected to ground so in this case LED will glow.

CASE III – When one input if logical high and other is logical low (A=0, B=1)

In this case we can easily see that Q5 is working as close circuit now. So the negative pin of the LED is connected to Q3 via Q5 and ultimately which is connected to ground so in this case LED will glow.

CASE IV – When both the inputs are logical high. (A=1, B=1)

In this case when both A and B are logical high then transistor Q1 and Q2 are also activated then the current will directly go from +5V junction to ground through Q1 and Q2 transistors, and will not got in the path where Q3 is connected as a result transistor Q3 will now act as open circuit and ultimately negative pin of LED is disconnected from ground so the LED will not glow.

The XOR or Exclusive OR Gate is a special type of logic gate used in digital electronics to perform the exclusive OR operation. The XOR gate takes two inputs and produces an output depending on the combination of the two inputs applied.

In, this article will explain the complete theory of the XOR gate along with its truth table, Boolean expression, logic symbol, circuit diagram, and more.