Truth Tables 

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_{ a}
Logic Gates Summary :: Learn all the details in the table below including ...
AND  NAND  OR  NOR  XOR  NOT  
Two ones give a one. Anything else gives 0. 
Two ones give a 0. Anything else gives 1. 
Two zeros give a 0. Anything else gives 1. 
Two zeros give a 1. Anything else gives 0. 
Equal inputs give a 0.  Input is inverted.  
A B Q
0 0 0
0 1 0
1 0 0
1 1 1

A B Q
0 0 1
0 1 1
1 0 1
1 1 0

A B Q
0 0 0
0 1 1
1 0 1
1 1 1

A B Q
0 0 1
0 1 0
1 0 0
1 1 0

A B Q 0 0 0 0 1 1 1 0 1 1 1 0 
A Q 0 1 1 0 







CMOS 4000 Series Chips  TTL 7400 Series Chips  Commonly Used Terms  
Technology  Complementary Metal Oxide Semiconductor  Transistor Transistor Logic  
LOW  A voltage less than 0.5 of the power supply  0 to 0.8 V  0, Zero, Off, Clear, False 
HIGH  A voltage greater than 0.5 of the power supply  2.2 to 5 V  1, One, On, Set, True 
Power  Extremely low power consumption  High power use compared with CMOS  
Speed  Slower  Faster 
Logic Goats :: Logic Gates Exercise
_{ d}These simulations are excellent for building logic and other circuits. This simulator can be used online or downloaded. Either way you will need to install the Java RunTime Environment if it is not already on your computer.
For the Falstad Circuit Simulation, CTRL+Click Make OR from NAND Gates
In options, check European Resistors and uncheck Conventional Current.
Click the Inputs to see it working
Alternatively view OR_from_NAND.txt.
Save or copy the text on the web page. Import the saved or copied text into the Falstad simulator.
Here is the new HTML5 Simulator Site.
BOOLE: A mathematician called Boole invented a branch of maths for processing true and false values instead of numbers. This is called Boolean Algebra. Simple Boolean algebra is consistent with common sense but if you need to process decisions involving many values that might be true or false according to complex rules, you need this branch of mathematics. Boolean algebra was invented long before the invention of logic gates!
_{ f}There are several types of gate. Each follows a very simple set of rules. By combining many gates in suitable ways, processing devices can be produced. A computer CPU chip can have millions of gates fabricated onto it. The table below shows several gates with two inputs. Many of these gates are also available in three, four and eight input versions.
Computers work using LOGIC. Displaying graphics such as the mouse cursor involves the XOR (Exclusive OR) operation. Addition makes use of AND and XOR.
_{ g}The one line descriptions of the rules below are clearer if shown in Truth Tables. These tables show the output for all possible input conditions. The inputs are always listed in the same order (counting in binary starting from zero).
_{ h}This is one of the simplest logic circuits that does something useful. It adds two bits together.
A B C S 0 plus 0 = 0 0 plus 1 = 1 1 plus 0 = 1 1 plus 1 = 1 0
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