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Autotransformer and voltage regulating transformer

Last Update Time: 2018-08-28 17:33:17

AC 220V power supply is used for radio tape recorder and TV set of power transformer household appliances, but DC power supply is used inside power transformer, so the voltage operation is different. This requires the power transformer to convert 220V (or 110V) power supply voltage into the required various AC voltage, and then rectifier, filter and other circuits to work properly. The primary coils of power transformers usually have a tap to accommodate different grid voltages, such as 20, 11010, etc. The two sides can have multiple windings to output different voltage and power according to the use condition. Power transformers have different rated power according to their usage.

Autotransformer and voltage regulating transformer

The common characteristic of transformer is that the DC circuit on both sides is completely separated, and the energy transfer on both sides is coupled by magnetic field. The autotransformer and voltage regulating transformer are another form of transformer. They have only one coil, and the input and output terminals are separated from the same coil by striking. There is a common end between one or both sides of the transformer, so their DC is no longer completely isolated. The tap of the autotransformer is fixed, that is, a portion of the voltage output from the primary side is fixed; on the other hand, the tap of the voltage regulator is used as the sliding joint of the brush, and the output voltage can be continuously adjusted as the brush moves. The rated power of the voltage regulator is 500 watts, 1kW, 2kW and so on.

Medium frequency transformer medium frequency transformer (also known as Zhou Zhong) can be applied from thousands of Hz to tens of MHz. The general transformer only adopts the principle of electromagnetic induction, and the intermediate frequency transformer also adopts the principle of parallel resonance. Therefore, the intermediate frequency transformer not only has the characteristics of transformer voltage, current and impedance, but also has resonance characteristics at a certain frequency. In superheterodyne radio, it plays the role of frequency selection and coupling, and determines sensitivity, selectivity and passband to a great extent. The resonant frequency of AM receiver is 465 kHz and the center frequency of IF transformer of FM semiconductor radio is 10.7 MHz and 100 kHz.