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Donn Stewart
13917 Deviar Dr
Centreville, VA 20120
dstew@cpuville.com

Designing, Building, and Selling Obsolete Computers -- for Educational Purposes -- since 2004

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Educational pages

I have here a group of pages that explain the basic elements of computer design. Each element is quite simple, but they can be combined to create larger circuits that make up a computer processor. These elements are usually thought of as electronic circuits, but they can also be made with mechanical or electro-mechanical parts. The important thing is the function of the element. However, you will see that I usually assume that we are dealing with electronic circuits.

These are the basic elements:

Logic gates and simple buffers


Flip-flops and registers


Three-state buffers


These basic elements can be combined to form larger units:

Decoders and multiplexors


Adders and other structures made using AND-OR array logic