Browse Definitions :
Definition

DC (direct current)

See also Ohm's Law.

DC (direct current) is the unidirectional flow or movement of electric charge carriers (which are usually electrons). The intensity of the current can vary with time, but the general direction of movement stays the same at all times. As an adjective, the term DC is used in reference to voltage whose polarity never reverses.

In a DC circuit, electrons emerge from the negative, or minus, pole and move towards the positive, or plus, pole. Nevertheless, physicists define DC as traveling from plus to minus.

Direct current is produced by electrochemical and photovoltaic cells and batteries. In contrast, the electricity available from utility mains in most countries is AC (alternating current). Utility AC can be converted to DC by means of a power supply consisting of a transformer, a rectifier (which prevents the flow of current from reversing), and a filter (which eliminates current pulsations in the output of the rectifier).

Virtually all electronic and computer hardware needs DC to function. Most solid-state equipment requires between 1.5 and 13.5 volts. Current demands can range from practically zero for an electronic wristwatch to more than 100 amperes for a radio communications power amplifier. Equipment using vacuum tubes, such as a high-power radio or television broadcast transmitter or a CRT (cathode-ray tube) display, require from about 150 volts to several thousand volts DC.

This was last updated in September 2005

Start the conversation

Send me notifications when other members comment.

Please create a username to comment.

-ADS BY GOOGLE

File Extensions and File Formats

SearchCompliance

  • compliance audit

    A compliance audit is a comprehensive review of an organization's adherence to regulatory guidelines.

  • regulatory compliance

    Regulatory compliance is an organization's adherence to laws, regulations, guidelines and specifications relevant to its business...

  • Whistleblower Protection Act

    The Whistleblower Protection Act of 1989 is a law that protects federal government employees in the United States from ...

SearchSecurity

  • RSA algorithm (Rivest-Shamir-Adleman)

    The RSA algorithm is the basis of a cryptosystem -- a suite of cryptographic algorithms that are used for specific security ...

  • remote access

    Remote access is the ability to access a computer or a network remotely through a network connection.

  • IP Spoofing

    IP spoofing is the crafting of Internet Protocol (IP) packets with a source IP address that has been modified to impersonate ...

SearchHealthIT

SearchDisasterRecovery

  • network disaster recovery plan

    A network disaster recovery plan is a set of procedures designed to prepare an organization to respond to an interruption of ...

  • virtual disaster recovery

    Virtual disaster recovery is a type of DR that typically involves replication and allows a user to fail over to virtualized ...

  • tabletop exercise (TTX)

    A tabletop exercise (TTX) is a disaster preparedness activity that takes participants through the process of dealing with a ...

SearchStorage

  • enterprise storage

    Enterprise storage is a centralized repository for business information that provides common data management, protection and data...

  • disk array

    A disk array, also called a storage array, is a data storage system used for block-based storage, file-based storage or object ...

  • optical storage

    Optical storage is any storage type in which data is written and read with a laser. Typically, data is written to optical media, ...

Close