Tuesday, March 8, 2011


Can you imagine modern living without electricity? No Aeroplanes would be able to take off, no car engines would run, radio and television broadcast would stop. In other words, modern living could not go on. Besides, millions of people mechanics factory, pilots etc would lose their jobs, for they can work only if electricity is available. Electricity is undoubtedly one of the most important aids to modern living.

Electricity is produces by a generator containing a coil of wire and magnet. The magnet is either straight or in the form a horse shoe. By moving the coil around outside of straight magnet electricity is generated.Another way is to turn the coil around inside of a horse shoe magnet. Or the coil can be held still and electricity is produces by moving the magnet backwards and forwards inside the coil. The electricity that we use in our daily life is generated in a power station. There you will find one or more big generators, which as operated by engine, steam, or water power. A large water wheel is found inside a power station which is run by a waterfall. This wheel is turned by the falling water, which pushes hard against its teeth. It turns round and round. A large shaft joins the wheel to a coil of wire. As the wheel turns, the coil turns too thus producing electricity.
On the same principles, steam power can be used to turn a turbine, which works like the water wheel. A shaft that joins the turbine to a coil of wire makes the coil turn as the turbine turns. Thus, electricity is produced. In a simple way, a coil can also be turned round by the power from a diesel engine. That is another way to produce electricity.
Electricity can produce light and heat, and perform various kinds of mechanical work such as lifting, turning, pulling, pushing and swinging. Electric current travels to our homes through wires in a complete circuit, and this is why there must be two pieces of wire connected to a bulb. In the bulb there is a fine wire that has high resistance against electric current. When the electric current passes through it, the energy used in overcoming the resistance will produce heat. When this fine wire becomes so hot that it shines, light is produced. A neon lamp usually in the form of a tube, however, produces light in a different way. Te tube is filled with neon gas. When the electric current passes through the gas, ultraviolet rays are formed. As the ultraviolet rays strike the inside of the tube, which is coated with a certain mineral, light is produced. The neon lamp produces more light for the same amount of electricity being used than the ordinary electric lamp. Moreover, its light is cool. In an electric stove or iron the electricity works almost in the same way as that in the ordinary electric lamp. 
The only difference is that in the two former utensils the wire has a higher resistance that enables it to produce more heat. This can be made by applying a wire of a different size and resistance.
Various kinds of mechanical work like those we have mentioned above can be performed by applying a dynamo to change the electricity into mechanic power, which is widely used in large factories, harbours, as well as in bridge and building construction.
Each electrical appliance uses a certain amount of electricity. When too many appliance are connects in the same circuit, the wire has to carry too heavy a load of electricity. A too heavily loaded wire will heat up and cause a fire, and this can be dangerous. Accordingly, a fuse is needed to break the circuit to stop the electric current. Inside the fuse there is a fine wire, which blows when too much electricity passes through it. The fuse is places as a part of the wire going to the house. This means that all electric current going to the house must pass through it. In short, the current will break automatically when the fuse blows. A short circuit occurs when two uncovered wires in the house touch each other so that the current flows directly from one wire to the other, causing too much current. To avoid this, all wires in the house must be covered or insulated with rubber or plastic.
Electricity is indeed a great aid to modern living, but at times it can be very dangerous, especially when you do not know how it work. So be careful.

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