Ohms, Amperes, and Volts Explained.
WHEN an electric current is flowing in the trolley wire or electric lighting circuit, there are three factors involved. One of these is the pressure expressed in volts which causes the current to flow; another is the resistance or opposition offered by the circuit to the flow which is expressed in ohms; the last is the current strength or volume, expressed in amperes, which is maintained in the circuit as a result of the pressure overcoming the resistance. The ohm is named in honor of George Simon Ohm, a distinguished German electrician. The volt is named after the Italian scientist, Volta. The ampere is named after the French scientist, Ampere. The unit of current is called the ampere. The unit of electrical pressure or electromotive force is called the volt. The unit of resistance is called the ohm. The unit of electric power is the volt-ampere, and this is called the watt. Seven hundred and forty-six watts per hour equal one horse-power. The unit of energy—the product of electric power and time—is called the joule, but this unit is too small for practical purposes and the kilowatt-hour is used instead. The kilowatt-hour is the work done by a thousand watts working for one hour. These electrical terms are as familiar to electrical engineers as feet and inches are to the average boy; the layman does not understand because he has never been taught, has never had to use the terms, has never read about them. It is easier to understand these terms if we consider electricity as a fluid and liken it to a current of water flowing through a pipe. The rate of flow of water in the pipe depends upon gravitation and the height of the reservoir or source above the outlet. The greater the height of the source, the greater will be the pressure of water and the greater the flow in gallons per minute. It is just the same with electricity. A current flows from a high potential to a low potential whenever the two are joined by a conducting wire. It is merely a difference of level. Watch a stream of water from the nozzle of a garden hose striking a bank of soft earth. Considering it as a stream of electricity, which unfortunately can not be seen, the force of the stream or its pressure represents voltage; the size of the stream or flow the amperage; the wattage the amount of work done in washing away the dirt. Suppose the interior of the nozzle and hose is rough, which offers a resistance to the ready flow of the stream; this friction and resistance is represented by ohms in an electric circuit.—Electric News Service.