This page will help you understand how the three basic logic gates function. The three basic gates are the AND, OR and the NOT.

The AND gate gives a HIGH output only when all of the inputs are HIGH. If any one of the inputs are LOW, the output is also LOW. This information about the gate can be represented in a truth table. Here is the AND gate truth table:

The AND gate can have more than two inputs. A binary HIGH will only be produced when all inputs are HIGH. As well as all other gates, this gate has a symbol used to represent it in a diagram:

The OR gate is a very simple gate. It delivers a HIGH output when any of the inputs are HIGH. The only way that an OR gate would produce a LOW output is if all of the inputs were LOW. With this said, here is the truth table and the symbol for the 2-input OR gate:

INPUT OUTPUT A B Y 0 0 0 0 1 1 1 0 1 1 1 1

Just like the AND gate, the OR gate can have more than two inputs. The OR gate would work it's logic the same way, only one inputs would have to be HIGH in order for the output to be HIGH.

The simplest of the three basic gates is the NOT gate. It is commonly called an inverter. The purpose of the NOT gate is to take the input, change it to its binary opposite, and output the inverted input. Unlike the AND or the OR Gates, the NOT gate can only have one input. Here is the truth table and symbol for the NOT gate: