Editing Digital electronics (section)

==Construction==
[[File:relogio binario.JPG|thumb|A [[binary clock]], hand-wired on [[breadboard]]s]]

A digital circuit is typically constructed from small electronic circuits called [[logic gate]]s that can be used to create [[combinational logic]]. Each logic gate is designed to perform a function of [[Boolean logic]] when acting on logic signals. A logic gate is generally created from one or more electrically controlled switches, usually [[transistor]]s but [[thermionic valve]]s have seen historic use. The output of a logic gate can, in turn, control or feed into more logic gates.

Another form of digital circuit is constructed from lookup tables, (many sold as "[[programmable logic device]]s", though other kinds of PLDs exist). Lookup tables can perform the same functions as machines based on logic gates, but can be easily reprogrammed without changing the wiring. This means that a designer can often repair design errors without changing the arrangement of wires. Therefore, in small-volume products, programmable logic devices are often the preferred solution. They are usually designed by engineers using [[electronic design automation]] software.

[[Integrated circuit]]s consist of multiple transistors on one silicon chip and are the least expensive way to make a large number of interconnected logic gates. Integrated circuits are usually interconnected on a [[printed circuit board]] which is a board that holds electrical components, and connects them together with copper traces.