Electrical Definitions


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Electrical Definitions

Letter - H

Head Guy

A guy fastened to the top of a telegraph pole.



The basic unit of inductance. One henry is the inductance which induces a cemf of 1 volt when the current is changing at the rate of 1 ampere per second.



A measurement of frequency. One hertz is equal to one inverse second (1/s); that is, one cycle per second, where a cycle is the duration between similar portions of a wave. HZ


High Intensity Discharge Lamps (HID.)

A general group of lamps consisting of mercury, metal halide, high-pressure sodium, and low pressure sodium lamps.


High Voltage

Voltage exceeds 600 volts.


High-Pressure Sodium Lamps

A sodium vapor in which the partial pressure of the vapor during operation is the order of 0.1 atmospheres.



Any shaftway, hatchway, well hole, or other vertical opening or space in which an elevator or dumbwaiter is designed to operate.


Hot Cathode Lamp

An electrical discharge lamp whose mode of operation is that of an arc discharge.


Hydroelectric Power

Power produced by using the power of water to turn the shaft of a generator.