Introduction to DLD

OR Gate Truth Table for 2, 3, 4, 5 Inputs

An OR gate is a digital logic gate that provides the output HIGH (1) when at least one input is HIGH (1). The output will be LOW (0) when all inputs are LOW (0). 

Let’s explain the truth tables of various inputs for an OR gate.

Truth Tables of OR Gate for Various Inputs

The following table shows the number of input combinations and the output behavior of OR gates with different numbers of inputs:

OR Gate Number of Inputs Possible Combinations
2-Input OR 2 4
3-Input OR 3 8
4-Input OR 4 16
5-Input OR 5 32

OR Gate Truth Table for 2 Inputs

The following diagram shows the OR Gate Truth Table for 2 Inputs

OR Gate Truth Table for 2 Inputs

Let’s explain the truth table of a 2-input OR logic gate.

  • A = 0, B = 0: Both inputs are LOW, so the output is 0 (LOW).
  • A = 0, B = 1: Input B is HIGH, so the output becomes 1 (HIGH).
  • A = 1, B = 0: Input A is HIGH, so the output becomes 1 (HIGH).
  • A = 1, B = 1: Both inputs are HIGH, so the output is 1 (HIGH).

OR Gate Truth Table for 3 Inputs

The following diagram shows the OR Gate Truth Table for 3 Inputs

OR Gate Truth Table for 3 Inputs

Let’s explain the truth table of a 3-input OR logic gate.

  • A = 0, B = 0, C = 1: Input C is HIGH, so the output is 1 (HIGH).
  • A = 0, B = 1, C = 0: Input B is HIGH, so the output is 1 (HIGH).
  • A = 0, B = 1, C = 1: Inputs B and C are HIGH, so the output is 1 (HIGH).
  • A = 1, B = 0, C = 0: Input A is HIGH, so the output is 1 (HIGH).
  • A = 1, B = 0, C = 1: Inputs A and C are HIGH, so the output is 1 (HIGH).
  • A = 1, B = 1, C = 0: Inputs A and B are HIGH, so the output is 1 (HIGH).
  • A = 1, B = 1, C = 1: All three inputs are HIGH, so the output is 1 (HIGH).

OR Gate Truth Table for 4 Inputs

The following diagram shows the OR Gate Truth Table for 4 Inputs

OR Gate Truth Table for 4 Inputs

Let’s explain the truth table of a 4-input OR logic gate.

  • A = 0, B = 0, C = 0, D = 0: All inputs are LOW, so the output is 0 (LOW).
  • A = 0, B = 0, C = 0, D = 1: Input D is HIGH, so the output is 1 (HIGH).
  • A = 0, B = 0, C = 1, D = 0: Input C is HIGH, so the output is 1 (HIGH).
  • A = 0, B = 0, C = 1, D = 1: Inputs C and D are HIGH, so the output is 1 (HIGH).
  • A = 0, B = 1, C = 0, D = 0: Input B is HIGH, so the output is 1 (HIGH).
  • A = 0, B = 1, C = 0, D = 1: Inputs B and D are HIGH, so the output is 1 (HIGH).
  • A = 0, B = 1, C = 1, D = 0: Inputs B and C are HIGH, so the output is 1 (HIGH).
  • A = 0, B = 1, C = 1, D = 1: Inputs B, C, and D are HIGH, so the output is 1 (HIGH).
  • A = 1, B = 0, C = 0, D = 0: Input A is HIGH, so the output is 1 (HIGH).
  • A = 1, B = 0, C = 0, D = 1: Inputs A and D are HIGH, so the output is 1 (HIGH).
  • A = 1, B = 0, C = 1, D = 0: Inputs A and C are HIGH, so the output is 1 (HIGH).
  • A = 1, B = 0, C = 1, D = 1: Inputs A, C, and D are HIGH, so the output is 1 (HIGH).
  • A = 1, B = 1, C = 0, D = 0: Inputs A and B are HIGH, so the output is 1 (HIGH).
  • A = 1, B = 1, C = 0, D = 1: Inputs A, B, and D are HIGH, so the output is 1 (HIGH).
  • A = 1, B = 1, C = 1, D = 0: Inputs A, B, and C are HIGH, so the output is 1 (HIGH).
  • A = 1, B = 1, C = 1, D = 1: All inputs are HIGH, so the output is 1 (HIGH).

OR Gate Truth Table for 5 Inputs

The following diagram shows the OR Gate Truth Table for 5 inputs

OR Gate Truth Table for 5 Inputs

Let’s explain the truth table of a 5-input OR logic gate.

  • A = 0, B = 0, C = 0, D = 0, E = 0: All inputs are LOW, so the output is 0 (LOW).
  • A = 0, B = 0, C = 0, D = 0, E = 1: Input E is HIGH, so the output is 1 (HIGH).
  • A = 0, B = 0, C = 0, D = 1, E = 0: Input D is HIGH, so the output is 1 (HIGH).
  • A = 0, B = 0, C = 0, D = 1, E = 1: Inputs D and E are HIGH, so the output is 1 (HIGH).
  • A = 0, B = 0, C = 1, D = 0, E = 0: Input C is HIGH, so the output is 1 (HIGH).
  • A = 0, B = 0, C = 1, D = 0, E = 1: Inputs C and E are HIGH, so the output is 1 (HIGH).
  • A = 0, B = 0, C = 1, D = 1, E = 0: Inputs C and D are HIGH, so the output is 1 (HIGH).
  • A = 0, B = 0, C = 1, D = 1, E = 1: Inputs C, D, and E are HIGH, so the output is 1 (HIGH).
  • A = 0, B = 1, C = 0, D = 0, E = 0: Input B is HIGH, so the output is 1 (HIGH).
  • A = 0, B = 1, C = 0, D = 0, E = 1: Inputs B and E are HIGH, so the output is 1 (HIGH).
  • A = 0, B = 1, C = 0, D = 1, E = 0: Inputs B and D are HIGH, so the output is 1 (HIGH).
  • A = 0, B = 1, C = 0, D = 1, E = 1: Inputs B, D, and E are HIGH, so the output is 1 (HIGH).
  • A = 0, B = 1, C = 1, D = 0, E = 0: Inputs B and C are HIGH, so the output is 1 (HIGH).
  • A = 0, B = 1, C = 1, D = 0, E = 1: Inputs B, C, and E are HIGH, so the output is 1 (HIGH).
  • A = 0, B = 1, C = 1, D = 1, E = 0: Inputs B, C, and D are HIGH, so the output is 1 (HIGH).
  • A = 0, B = 1, C = 1, D = 1, E = 1: Inputs B, C, D, and E are HIGH, so the output is 1 (HIGH).
  • A = 1, B = 0, C = 0, D = 0, E = 0: Input A is HIGH, so the output is 1 (HIGH).
  • A = 1, B = 0, C = 0, D = 0, E = 1: Inputs A and E are HIGH, so the output is 1 (HIGH).
  • A = 1, B = 0, C = 0, D = 1, E = 0: Inputs A and D are HIGH, so the output is 1 (HIGH).
  • A = 1, B = 0, C = 0, D = 1, E = 1: Inputs A, D, and E are HIGH, so the output is 1 (HIGH).
  • A = 1, B = 0, C = 1, D = 0, E = 0: Inputs A and C are HIGH, so the output is 1 (HIGH).
  • A = 1, B = 0, C = 1, D = 0, E = 1: Inputs A, C, and E are HIGH, so the output is 1 (HIGH).
  • A = 1, B = 0, C = 1, D = 1, E = 0: Inputs A, C, and D are HIGH, so the output is 1 (HIGH).
  • A = 1, B = 0, C = 1, D = 1, E = 1: Inputs A, C, D, and E are HIGH, so the output is 1 (HIGH).
  • A = 1, B = 1, C = 0, D = 0, E = 0: Inputs A and B are HIGH, so the output is 1 (HIGH).
  • A = 1, B = 1, C = 0, D = 0, E = 1: Inputs A, B, and E are HIGH, so the output is 1 (HIGH).
  • A = 1, B = 1, C = 0, D = 1, E = 0: Inputs A, B, and D are HIGH, so the output is 1 (HIGH).
  • A = 1, B = 1, C = 0, D = 1, E = 1: Inputs A, B, D, and E are HIGH, so the output is 1 (HIGH).
  • A = 1, B = 1, C = 1, D = 0, E = 0: Inputs A, B, and C are HIGH, so the output is 1 (HIGH).
  • A = 1, B = 1, C = 1, D = 0, E = 1: Inputs A, B, C, and E are HIGH, so the output is 1 (HIGH).
  • A = 1, B = 1, C = 1, D = 1, E = 0: Inputs A, B, C, and D are HIGH, so the output is 1 (HIGH).
  • A = 1, B = 1, C = 1, D = 1, E = 1: All inputs are HIGH, so the output is 1 (HIGH).