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

Powered by:

SearchCompliance

SearchSecurity

  • password

    A password is an unspaced sequence of characters used to determine that a computer user requesting access to a computer system is...

  • adware

    Adware is any software application in which advertising banners are displayed while a program is running.

  • botnet

    A botnet is a collection of internet-connected devices, which may include PCs, servers, mobile devices and internet of things ...

SearchHealthIT

SearchDisasterRecovery

  • call tree

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

  • mass notification system (MNS)

    A mass notification system is a platform that sends one-way messages to inform employees and the public of an emergency.

  • disaster recovery as a service (DRaaS)

    One approach to a strong disaster recovery plan is DRaaS, where companies offload data replication and restoration ...

SearchStorage

  • compact disc (CD)

    A compact disc is a portable storage medium that can be used for recording, storing and playing back audio, video and other data ...

  • secondary storage

    Secondary storage is used to protect inactive data written from a primary storage array to a nonvolatile tier of disk, flash or ...

  • VRAM (video ram)

    VRAM (video RAM) is a reference to any type of random access memory (RAM) used to store image data for a computer display.

SearchSolidStateStorage

  • SSD RAID (solid-state drive RAID)

    SSD RAID (solid-state drive RAID) is a methodology commonly used to protect data by distributing redundant data blocks across ...

  • Tier 0

    Tier 0 (tier zero) is a level of data storage that is faster, and perhaps more expensive, than any other level in the storage ...

  • PCIe SSD (PCIe solid-state drive)

    A PCIe SSD (PCIe solid-state drive) is a high-speed expansion card that attaches a computer to its peripherals.

SearchCloudStorage

  • 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 ...

  • Zadara VPSA and ZIOS

    Zadara Storage provides block, file or object storage with varying levels of compute and capacity through its ZIOS and VPSA ...

Close