AND Gate using transistors

Published: 01 January 2026

The AND Gate is a basic digital logic gate that implements the logical AND function. It has two inputs and one output.
The output is high only when both inputs are high. The full truth table showing all input and output states can be found below. Each row represents a physical state of the circuit.

Truth table

Input A Input B Output
0 0 0
0 1 0
1 0 0
1 1 1

Circuit scheme

The inputs and output in the schematic correspond to the truth table headers.

Implementation

For the implementation, NPN 2N2222A transistors were used. The output LED resistor was omitted; however, it is required for proper operation.

The video demonstrates the circuit behavior for all input states.