WHAT IS A WATT?

Temuka Leader, Issue 10362, 7 September 1922, Page 2

WHAT IS A WATT?

HOW ELECTRICITY IS - MEASURED; . The language of the electrician i Greek to most people. Whilst h talks globly of volts and ampere and watts, they know only that the, have to pay an electric light bill fo so many units, and let it go at'that Though electricity is not a fluid we can understand most, of its term by comparing it with water, flowinj through a ■ pipe. If we turn- i stream of water on to the paddles r a Water wheel, the work that , tin wheel will do depends on two thing. l —the amount of water deliveret every second and the pressure of tip stream. We measure the first ir gallons and the second in pounds. FINDING THE COST. In the case of electricity, we measure the rate at which it flows in amperes, and its pressure in volts. The work which it will do is found by multiplying amperes and volts together, which gives the answer in watts, or .units of energy. The Board of Trade unit is 1000 watts, often called a kilowatt, which is the electrical equivalent of one horse-power. You will find the number of watts they require engraved on most electric lamps, and from this you can discover what they will cost to use. A 25-watt lamp will use one unit of 1000 watts in forty hours’ burning, and if electricity costs tehpence a unit, the lamp will work out at a farthing an hour. The ohm is another electrical measurement which can be understood by a comparison with water, pipe, but if the pipe is narrow, only Water flows easily through a largo a, small quantity can force its way through. What the pipe is to water, the wire is to electricity. The smaller the wire, the more difficult electricity will find it to pass, because the fine wire resists its flow. The electrician measures wires by their resistance in ohms.