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

SearchCompliance

  • information governance

    Information governance is a holistic approach to managing corporate information by implementing processes, roles, controls and ...

  • enterprise document management (EDM)

    Enterprise document management (EDM) is a strategy for overseeing an organization's paper and electronic documents so they can be...

  • risk assessment

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

SearchSecurity

  • spam trap

    A spam trap is an email address that is used to identify and monitor spam email.

  • honeypot (computing)

    A honeypot is a network-attached system set up as a decoy to lure cyber attackers and detect, deflect and study hacking attempts ...

  • cracker

    A cracker is someone who breaks into someone else's computer system, often on a network; bypasses passwords or licenses in ...

SearchHealthIT

SearchDisasterRecovery

  • risk mitigation

    Risk mitigation is a strategy to prepare for and lessen the effects of threats faced by a business.

  • call tree

    A call tree is a layered hierarchical communication model that is used to notify specific individuals of an event and coordinate ...

  • Disaster Recovery as a Service (DRaaS)

    Disaster recovery as a service (DRaaS) is the replication and hosting of physical or virtual servers by a third party to provide ...

SearchStorage

  • cloud testing

    Cloud testing is the process of using the cloud computing resources of a third-party service provider to test software ...

  • storage virtualization

    Storage virtualization is the pooling of physical storage from multiple storage devices into what appears to be a single storage ...

  • erasure coding

    Erasure coding (EC) is a method of data protection in which data is broken into fragments, expanded and encoded with redundant ...

Close