スポンサーサイト

  • 2015.04.22 Wednesday
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  • by スポンサードリンク

一定期間更新がないため広告を表示しています


filter capacitor

The switching power supply, as the name implies, is there a door, a door through a closed power supply, power supply is stopped by the door, so what is it, switching power supply in some adopts the controllable silicon, or by the switch tube, the two components with similar performance, is to rely on base, ( switch ) control pole ( SCR ) plus pulse signals to complete the turn-on and turn-off, pulse signal is a half weeks of arrival, control electrode voltage increases, the switch tube or a controlled silicon is conducted by 220V, rectifier, filter output 300V voltage is conducted through the switch, transformer to the secondary, and through the transformation ratio of the the voltage is increased or decreased, for each circuit.dvb receivers Oscillation pulsed negative half period arrival, power adjust tube base, or to the control electrode of the controlled silicon voltage is lower than the original set voltage, the power adjust tube cutoff, 300V power supply is shut off, switch the transformer secondary no voltage, then the circuit required working voltage on the road, secondary rectified filter capacitor discharge maintain wedding.

Up until the time of the next pulse cycle positive half cycle signal arrives, repeat the last process. The switch transformer is the transformer, because his work frequency is higher than that of 50HZ low frequency. Then push the switch tube or SCR pulse to obtain it, it would be necessary for a oscillation circuit generates, we know, crystals of the three transistor has a characteristic, is the base to emitter voltage is 0.65-0.7V amplification, 0.7V above is saturated conduction state, - 0.1V - - 0.3V work in the oscillatory state, then the the working point after a good tune, rely on deep negative feedback to generate negative pressure, so that the oscillation tube vibration, oscillation frequency by the tube base of capacitor charging and discharging the length of time to decide, oscillation frequency high output pulse amplitude is large, it is small, this decided the power adjust tube output voltage size physiotherapy.

Then the transformer secondary output voltage to voltage, generally in the switch transformer, single winding a coil group, at the upper end of the voltage obtained by rectifying and filtering, as a reference voltage, and then through a photoelectric coupler, the reference voltage to return the oscillation tube base, to adjust the vibration frequency, if the secondary of the transformer voltage increases, the sampling coil output voltage is also increased by a photoelectric coupler, obtained positive feedback voltage increases, the voltage applied to the oscillation tube base, makes the oscillation frequency is reduced, to stabilize the secondary output voltage stability, very fine work needn't fine said, also need not know as fine, so that high power voltage by transformer switch transfer, and later separated, return the sampling voltage by optical transfer and grade separated, so the former class of electric voltage, was associated with later stage separation, this is called cold plate, is safe, before the power supply transformer is independent, this is called switching power supply agnesf.


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