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internacionalizmy in English, TWO KINDS OF ELECTRICITY Two different kinds of electricity are used to operate electronic apparatus. One kind is called direct current, usually abbreviated with to DC. This is the kind of electricity we get from a battery, the flow of current is in one direction only. The other kind is alternating current, usually known as AC. This is the kind of electricity which is generated in power stations for domestic and industrial use. It is called alternating current because the direction of flow of electrons changes. The number of changes of current direction in every second, so-called cycles, is known as the frequency. The frequency of alternating current in most parts of Europe is 50 cycles. In North America it is 60 cycles. Very high frequencies are used in radio communication, sometimes several million cycles. Some complicated pieces of electrical apparatus, for example radio and television receivers, do not use direct current, but alternating. As the domestic supply is alternating current, it is therefore necessary to change it to direct current inside the apparatus. This change, or conversion, is brought about by means of a rectifier, sometimes called a diode. A simple diode consists of a valve which has only two electrodes, one is the anode and the other the cathode. When it is used to rectify, it will pass current only during each half cycle of the applied alternating current. The result is a pulsating current flowing in one direction, an irregular or uneven current, but a direct current. It can be made regular and even by means of a smoothing circuit.
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