# digital circuit

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Related to digital circuit: Analog circuit

## digital circuit,

electronic circuit that can take on only a finite number of states. That is contrasted with analog circuitsanalog circuit,
electronic circuit that operates with currents and voltages that vary continuously with time and have no abrupt transitions between levels. Generally speaking, analog circuits are contrasted with digital circuits, which function as though currents or voltages
, whose voltages or other quantities vary in a continuous manner. Binary (two-state) digital circuits are the most common. The two possible states of a binary circuit are represented by the binary digits, or bits, 0 and 1. The states are also commonly referred to as "on" and "off" or "high" and "low" (see information theoryinformation theory
or communication theory,
mathematical theory formulated principally by the American scientist Claude E. Shannon to explain aspects and problems of information and communication.
). The simplest forms of digital circuits are built from logic gates, the building blocks of the digital computercomputer,
device capable of performing a series of arithmetic or logical operations. A computer is distinguished from a calculating machine, such as an electronic calculator, by being able to store a computer program (so that it can repeat its operations and make logical
. Since most of the physical variables encountered in the real world, e.g., position and temperature, exist in analog form, they are represented electrically by continuously varying currents and voltages in analog circuits. To make digital and analog circuits compatible special converters are used—either analog-to-digital or digital-to-analog depending on the direction of information flow. Digital circuits simulate continuous functions with strings of bits; the more bits that are used, the more accurately the continuous signal can be represented. For example, if 16 bits are used to represent a varying voltage, the signal can be assigned one of more than 65,000 different values. Digital circuits are more immune to noise than analog circuits, and digital signals can be stored and duplicated without degradation (see compact disccompact disc
(CD), a small plastic disc used for the storage of digital data. As originally developed for audio systems, the sound signal is sampled at a rate of 44,100 times a second, then each sample is measured and digitally encoded on the 4 3-4 in (12 cm) disc as a series of
). Digital circuits can often manipulate signals more effectively—and less expensively—than analog circuits. Those reasons helped digital systems to succeed over all analog contenders for proposed high-definition television in the United States.

## digital circuit

[′dij·əd·əl ′sər·kət]
(electronics)
A circuit designed to respond at input voltages at one of a finite number of levels and, similarly, to produce output voltages at one of a finite number of levels.

## digital circuit

An electronic circuit that accepts and processes binary data (on/off) according to the rules of Boolean logic (AND, OR, NOT, etc.). See chip and Bebop to the Boolean Boogie.

Digital Plumbing!
A digital circuit can be conceptualized as a mass of plumbing. The circuit paths are the pipes, the transistors are the valves and the electricity is the water. Imagine opening a valve, and the water that passes through it and down a pipe will eventually reach a second valve, causing it to turn on, allowing water in another pipe to flow through it that reaches another valve, and so on.

A resistor can be viewed as a large pipe that narrows into a smaller pipe, a capacitor as a storage tank and a diode as a one-way valve, allowing water to flow in only one direction.

From Logic to Plumbing It would be a plumber's worst nightmare to have to follow the maze of pipes (circuits) that are really created in a chip. This simple circuit actually resides in every computer. For more details, see chip.
References in periodicals archive ?
As a result, system LSIs for digital circuits and system LSIs for analog circuits are required separately.
Providing designers with the tools they need to lay out digital circuit boards for fast logic and to get designs working the first time around, Digital Circuit Boards:
The concepts presented are applicable to analog and digital circuits operating from below audio frequencies to those in the GHz range.
Digital Circuit Solutions is located in the Globe Center in Morrisville, where it has a modern 70,000 square foot manufacturing facility that features the latest manufacturing and repair technologies.
The company is developing new System-on-Chip (SOC) products using its analog and digital circuit designs and Micro-Electromechanical Systems (MEMS) technology for the consumer, automotive, communications and medical markets.
Katz (Department of Electrical and Computer Engineering, Drexel University) introduces the art and science of designing digital circuits in this text/CD-ROM package for undergraduates.

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