Browse Definitions:
Definition

watt

The watt (abbreviated W) is the International System of Units' (SI) standard unit of power (energy per unit time), the equivalent of one jouleper second. The watt is used to specify the rate at which electrical energy isdissipated, or the rate at which electromagnetic energy is radiated, absorbed, or dissipated.

In DC (direct-current) and low-frequency AC (alternating current) electrical circuits andsystems, power is the product of the current and the voltage. Power is alsoproportional to the ratio of the square of the voltage to the resistance, and to the product of the resistanceand the square of the current. Consider a circuit in which the current, voltage, andresistance are all constant. If the current in amperes is represented by I,the voltage (or potential difference) in volts is represented by E, and theresistance in ohms is represented by R, then the following equations hold forpower in watts, represented by P:

P = EI

P = E2/R

P = I2R

In radio-frequency (RF) circuits and systems, the calculation of powerbecomes more complex. This is because, at high frequencies, AC is affected not onlyby resistance, but by reactance. Inthese situations, no simple formulas exist for the calculation of power. However,dissipated or radiated RF power in can be determined by direct measurement using aninstrument called an RF wattmeter.

In situations involving very high or very low power, prefix multipliersare commonly used to obtain power units. As the rate of dissipated or radiated powerincreases, one kilowatt (kW) is equal to 1000 W; one megawatt (MW) is equal to 106W; one gigawatt (GW) is equal to 109 W. As power decreases, one milliwatt(mW) is equal to 0.001 W; one microwatt (µW) is equal to 10-6 W; one nanowatt(nW) is equal to 10-9 W.

This was last updated in April 2005

Join the conversation

1 comment

Send me notifications when other members comment.

By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy

Please create a username to comment.

Best..
Cancel

-ADS BY GOOGLE

File Extensions and File Formats

SearchCompliance

  • pure risk (absolute risk)

    Pure risk, also called absolute risk, is a category of threat that is beyond human control and has only one possible outcome if ...

  • risk assessment

    Risk assessment is the identification of hazards that could negatively impact an organization's ability to conduct business.

  • audit program (audit plan)

    An audit program, also called an audit plan, is an action plan that documents what procedures an auditor will follow to validate ...

SearchSecurity

SearchHealthIT

SearchDisasterRecovery

  • business continuity and disaster recovery (BCDR)

    Business continuity and disaster recovery (BCDR) are closely related practices that describe an organization's preparation for ...

  • business continuity plan (BCP)

    A business continuity plan (BCP) is a document that consists of the critical information an organization needs to continue ...

  • call tree

    A call tree -- sometimes referred to as a phone tree -- is a telecommunications chain for notifying specific individuals of an ...

SearchStorage

  • nearline storage

    Nearline storage is the on-site storage of data on removable media.

  • application-aware storage

    Application-aware storage is a storage system with built-in intelligence about relevant applications and their utilization ...

  • Remote Direct Memory Access (RDMA)

    Remote Direct Memory Access (RDMA) is a technology that allows computers in a network to exchange data in main memory without ...

SearchSolidStateStorage

  • 3D XPoint

    3D XPoint is memory storage technology jointly developed by Intel and Micron Technology Inc.

  • RRAM or ReRAM (resistive RAM)

    RRAM or ReRAM (resistive random access memory) is a form of nonvolatile storage that operates by changing the resistance of a ...

  • JEDEC

    JEDEC is a global industry group that develops open standards for microelectronics.

SearchCloudStorage

  • Google Cloud Storage

    Google Cloud Storage is an enterprise public cloud storage platform that can house large unstructured data sets.

  • RESTful API

    A RESTful application program interface breaks down a transaction to create a series of small modules, each of which addresses an...

  • cloud storage infrastructure

    Cloud storage infrastructure is the hardware and software framework that supports the computing requirements of a private or ...

Close