OR gate

OR gate truth table
Input		Output
A	B	A OR B
0	0	0
0	1	1
1	0	1
1	1	1

In digital electronics, an OR gate is a logic gate which produces an output of true when any of its inputs are true. A LOW (0) output results when all of the inputs to the gate are LOW; if any of the inputs are HIGH (1), a high output results.

Logic

A two-input OR gate can be expressed in Boolean logic as $A+B$ or $A\lor B$.

Alternatives

If a specific type of gate is not available, a circuit that implements the same function can be constructed from other available gates. Through the use of the "universal" NAND gates and NOR gates, almost any other Boolean logic gate can be constructed.

An OR gate can be constructed using three NAND gates or two NOR gates in the following topologies:

See also

• AND gate
• NAND gate
• NOR gate
• XOR gate
• XNOR gate
• Inverter (NOT gate)
• IMPLY gate
• NIMPLY gate