Measuring Electricity.

Pelorus Guardian and Miners' Advocate., Volume 29, Issue 18, 6 March 1917, Page 2

Measuring Electricity.

HOW THE TERMS WERE

ORIGINATED,

The terma jolt, ampere, ohm, watt, and farad, met with in works on electricity, mean very little-to most people. The volt is the unit of electrical pressure ; the ampere, the unit of current strength ; the ohm, the unit of resistance ; the watt, the unit of electric power ; and the least of all known, the unit of electrical capacity.

Current strength is determined by dividing the pressure by the strength thus the number of amperes of current strength is equal to the number of valts divided by the number of ohms. The watt Indicates the amount of electric energy being used when an ampere of current is flowing under a pressure of one volt. However, the term kilowatt, or one thousand watts, is" more generally used. The unit of electrical capacity, the farad, will contain one ampere of current at one volt pressure for one second of time. The farad is divided into a million equal parts, each part termed the microfarad, and this is the terra most used in stating electrical capacity.

The five terms used in measuring electricity were all derived from the names of the five greatest pioneers m -leotrical development, but strange ns it may seem, none of these men 1.a.3 anything to do with the discover of the particular unit named after him. The names wore arbitrarily pflixcd years later to perpetuate the names of the pioneer electrical geniuses.

The term ‘‘volt 1 ' la derived from the name of Alessandro Volta, an Italian, horn in 171.”.. fie was one of the first men to try in harness electricity, yet h<* died without . the knowledge that a "volt" was the pressure necessary to force one ampere of current through a conductor having one ohm resistance.

Likewise, Andrle Ampere, father of the science of electro-dynamics, never knew that an "ampere’ was equal to the number of volts of pressure divided by the ohms of resistance. He was born in France in 1755. George Simon Ohm was the author of what, is known as Ohm’s Law, now universally recognised as the unit for measuring the resistance of electricity, but it was not until years later that the unit of resistance was named after the German physicist. The number of ohms is computed by dividing the number'of volts by the number of amperes. With either of the two units known the third can easily be found. Likewise, electrical energy is as easily figured. The “watt" indicates the amount of electric energy being used when one ampere of current is flowing under a pressure of one volt. The watt is derived from the name of James Watt, the man who really invented the modern steam engine. Without the principle of the steam engine, however, electricity as a motive power could not do the powerful tasks it daily accomplishes. Michael Faraday made the great discovery of magnetic electric currents, the principle on which all modern dynamos and transformers are constructed. In recognition of his great work scientists have named the unit of capacity the “farad." This unit of capacity will contain one ampere of current at one volt treasure for one second of time.