Electronic Engineering Dictionary

Power. The rate of doing work or the rate of expending energy. The unit of electrical power is the watt.

Power Amplifier. An amplifier in which the output-signal power is greater than the input-signal power. A amplifier designed to drive a speaker or other transducer. An amplifier with a relatively large power gain when compared to other amplifiers in the same class, or driving the same load.

Power Bandwidth: The frequency range of an amplifier over which the amp will deliver at least half the rated power.

Power Budget: The allocation, within a system, of available electrical power, among the various functions that need to be performed.

Power Cable. Two or more insulated conductors (solid or stranded) contained in a common covering, or two or more insulated conductors twisted or molded together without a common covering, or one insulated conductor with a metallic covering, shield, or outer conductor. The rated working voltage must be 300 volts or more, and the size of each individual conductor must be number 18AWG or larger. Also refer to Manufacturers of Power Cables.

Power Circuit. Electrical loads where the voltage and current exceed the minimum arcing conditions of the contact material. As a general rule, application loads in excess of 8 volts 0.5 ampere are considered power circuits.

Power Cord. A cable assembly having both a female end and male end used to supply AC power between units or systems. Manufacturers of Power Cords and power cable [cable with out an attached connector].

Power Derating. Reducing a components power rating based on increasing ambient temperature, see Derating.

Power Factor. The ratio of the actual power of an alternating or pulsating current, as measured by a wattmeter, to the apparent power, as indicated by ammeter and voltmeter readings. The power factor of an inductor, capacitor, or insulator is an expression of their losses. In AC power transmission and distribution, the cosine of the phase angle between the voltage and current.

Power Fault. A condition on a power line that results in the supply voltage having a value other than normal.

Power Fault Monitor. A circuit or component that monitors the voltage power line and outputs a signal to indicate an over-voltage or under-voltage.

Power Frequency. The frequency of the AC power; 60Hz in the United States, but having different frequencies in other countries.

Power Loss. The electrical power, supplied to a circuit, that does no work and is usually dissipated as heat. The heat loss in a conductor as current flows through it.

Power Meter. A device used to measure power. Also refer to Manufacturers of Power Meters, and Optical Power Meters.

Power-on Reset. A circuit that outputs a reset during the power on sequence or after the circuit has reach a particular voltage. Read more about Power On Reset Circuits.

Power Pentode. A special purpose tube used to provide high-current gain or power amplification. Each grid wire is directly in line with the one before and after it, a fact which allows more electrons to reach the plate. Also refer to Vacuum Tube.

Power Plug. The male end of a connector system used to transmit power. The removable side of an AC connection, as shown to the right. Also refer to Manufacturers of Power Connectors.

Power Rating. The maximum power a component can dissipate under given conditions. The maximum amount of power a component or device can safely dissipate without damage.

Power Standing-Wave Ratio. [PSWR] The ratio of the square of the maximum and minimum voltages of a transmission line.

Power Supply. A unit that supplies electrical power to another unit. It changes ac to dc and maintains a constant voltage output within limits. [Power Supply Manufacturers].

Power supply rejection ratio. [PSRR] The ratio of the change in input offset voltage to the corresponding change in value of one power supply voltage with all remaining power supply voltages held constant.