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
SearchNetworking
SearchSecurity
  • man in the browser (MitB)

    Man in the browser (MitB) is a security attack where the perpetrator installs a Trojan horse on the victim's computer that is ...

  • Patch Tuesday

    Patch Tuesday is the unofficial name of Microsoft's monthly scheduled release of security fixes for the Windows operating system ...

  • parameter tampering

    Parameter tampering is a type of web-based cyber attack in which certain parameters in a URL are changed without a user's ...

SearchCIO
  • e-business (electronic business)

    E-business (electronic business) is the conduct of business processes on the internet.

  • business resilience

    Business resilience is the ability an organization has to quickly adapt to disruptions while maintaining continuous business ...

  • chief procurement officer (CPO)

    The chief procurement officer, or CPO, leads an organization's procurement department and oversees the acquisitions of goods and ...

SearchHRSoftware
SearchCustomerExperience
  • first call resolution (FCR)

    First call resolution (FCR) is when customer service agents properly address a customer's needs the first time they call.

  • customer intelligence (CI)

    Customer intelligence (CI) is the process of collecting and analyzing detailed customer data from internal and external sources ...

  • clickstream data (clickstream analytics)

    Clickstream data and clickstream analytics are the processes involved in collecting, analyzing and reporting aggregate data about...

Close