Logic Gates

I am currently taking a Computer Architecture course and my teacher explained Logic Gates in class. I did not really understand them so I came home and looked into them further. I found some links and took some notes that I think explain them quite well. Good Luck and comment if you have any questions!

AND Gate:

The AND gate has an output that is normally at logic level 0, but goes HIGH to logic level 1 when all inputs are at logic level 1.

"If both A and B are true, then Q is true"

Helpful Links:

http://www.electronics-tutorials.ws/logic/logic_2.html

OR Gate:

The output of an OR gate is true if one or more if the inputs are true, but if all are false it outputs false.

Helpful Links:

Check out a live simulation: http://logic.ly/lessons/or-gate/

NOT Gate: Digital Inverter

The NOT gate is a single input device that has a normal output level of 1 and goes LOW at logic level 0 when an input is of logic level 1. So, it inverts the input signal. 

"If A is not true, then Q is true"

Helpful Links:

http://www.electronics-tutorials.ws/logic/logic_4.html

NAND Gate:

The NAND gate is a combination of the AND gate and the NOT gate (NOT + AND = NAND). It only produces an output when any of its outputs are NOT present. So, this means that it will only return true when any of its inputs are false. 

"If either A or B is not true, then Q is true"

Helpful Links: 

http://www.electronics-tutorials.ws/boolean/bool_4.html

http://www.electronics-tutorials.ws/logic/logic_5.html