Logic OR Gates: What Is An OR Gate

In the context of electronic circuits, an OR gate is an integrated circuit (IC) that switches on if one of multiple conditions is true (true equates to 1). ‘True’ in this context is the output pin that is ‘HIGH’ or ‘ON’. For example: An OR gate with two electrical input pins will switch on its output pin if one of its input pins is ‘HIGH’ or ‘ON’. If both inputs are on, then the output will be on as well. How an OR gate behaves:

• If input pin 1 = off and input pin 2 = off, then output pin = off (LOW).
• If input pin 1 = on and input pin 2 = on, then output pin = on (HIGH).
• If input pin 1 = on and input pin 2 = off, then output pin = on (HIGH).
• If input pin 1 = off and input pin 2 = on, then output pin = on (HIGH).

All an OR gate requires to switch on is for one of its inputs to be HIGH or ON.

Further Reading

Logic AND Gates: What Is An ‘AND’ gate

Logic NOR gates: Understanding NOR Gate Operation