OR Gate
| Input A | Input B | Output |
|---|---|---|
| false | false | false |
| false | true | true |
| true | false | true |
| true | true | true |
An OR gate is a digital logic gate with two or more inputs and one output that performs logical disjunction. The output of an OR gate is true when one or more of its inputs are true. If all of an OR gate's inputs are false, then the output of the OR gate is false.
The truth table for an OR gate with two inputs appears to the right.
Symbols
Each of the symbols below can be used to represent an OR gate. There are multiple international standards defined, and one may preferred over the other in your region of the world.
| ASNI / IEEE | IEC |
|---|---|
 |  |
Live Example
Try the following interactive example to see for yourself how an OR gate behaves.
Further Reading
To learn more, check out the following external resources:
OR gate on Wikipedia
Multiple-input gates on All About Circuits
Basic Logical Functions and Gates at Play-Hookey
Simulate with Logicly
Logicly provides an engaging, hands-on learning environment for teaching logic gates and circuits. Download the Free 30-Day Trial today to evaluate Logicly in your classroom or lab. Learn More »
