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  2. Volt-ampere - Wikipedia

    en.wikipedia.org/wiki/Volt-ampere

    The volt-ampere (SI symbol: VA, [1] sometimes V⋅A or V A) is the unit of measurement for apparent power in an electrical circuit. It is the product of the root mean square voltage (in volts) and the root mean square current (in amperes). [2] Volt-amperes are usually used for analyzing alternating current (AC) circuits.

  3. Watt - Wikipedia

    en.wikipedia.org/wiki/Watt

    Power is the rate at which energy is generated or consumed and hence is measured in units (e.g. watts) that represent energy per unit time. For example, when a light bulb with a power rating of 100 W is turned on for one hour, the energy used is 100 watt hours (W·h), 0.1 kilowatt hour, or 360 kJ. This same amount of energy would light a 40 ...

  4. Volt - Wikipedia

    en.wikipedia.org/wiki/Volt

    The volt (symbol: V) is the unit of electric potential, ... watts per ampere (power per current), or joules per coulomb (energy per charge), ...

  5. AC power - Wikipedia

    en.wikipedia.org/wiki/AC_power

    A capacitor is a device that stores energy in the form of an electric field. As current is driven through the capacitor, charge build-up causes an opposing voltage to develop across the capacitor. This voltage increases until some maximum dictated by the capacitor structure. In an AC network, the voltage across a capacitor is constantly changing.

  6. Electric power - Wikipedia

    en.wikipedia.org/wiki/Electric_power

    Electric power is the rate of transfer of electrical energy within a circuit.Its SI unit is the watt, the general unit of power, defined as one joule per second.Standard prefixes apply to watts as with other SI units: thousands, millions and billions of watts are called kilowatts, megawatts and gigawatts respectively.

  7. Power rating - Wikipedia

    en.wikipedia.org/wiki/Power_rating

    Power ratings are usually given in watts for real power and volt-amperes for apparent power, although for devices intended for use in large power systems, both may be given in a per-unit system. Cables are usually rated by giving their maximum voltage and their ampacity . [ 4 ]

  8. Alternating current - Wikipedia

    en.wikipedia.org/wiki/Alternating_current

    A schematic representation of long distance electric power transmission. From left to right: G=generator, U=step-up transformer, V=voltage at beginning of transmission line, Pt=power entering transmission line, I=current in wires, R=total resistance in wires, Pw=power lost in transmission line, Pe=power reaching the end of the transmission line, D=step-down transformer, C=consumers.

  9. Wattmeter - Wikipedia

    en.wikipedia.org/wiki/Wattmeter

    For each sample, the voltage is multiplied by the current at the same instant; the average over at least one cycle is the real power. The real power divided by the apparent volt-amperes (VA) is the power factor. A computer circuit uses the sampled values to calculate RMS voltage, RMS current, VA, power (watts), power factor, and kilowatt-hours.