Power supply filter circuit analysis of the following points to note

(1) analyze the working principle of the filter capacitor, the main use of capacitors, "straight through the cross" characteristics, or charging and discharging characteristics, that is, the rectifier circuit output unidirectional pulsating DC voltage on the filter capacitor charging, when there is no unidirectional pulsating DC voltage output, the filter capacitor discharged to the load.

(2) analyze the working principle of the filter inductor, mainly to recognize the inductor on the DC resistance is very small, no inductive resistance, and the presence of AC inductive resistance.

(3) electronic filter itself does not have a voltage regulator, but after adding a voltage regulator diode can make the output DC voltage is more stable.

(4) When analyzing electronic filter circuits, it is important to know that the capacitance on the base of the electronic filter tube is the key element of filtering. In addition, to analyze the DC circuit, the electronic filter tube has a base current and collector, emitter current, the current flowing through the load is the emitter current of the electronic filter tube, change the size of the base current can be adjusted to the electronic filter tube collector and the emitter of the tube voltage drop between the electronic filter tube, so as to change the size of the output DC voltage of the electronic filter.