What is a filter film capacitor?

The film capacitor is a capacitor in which a metal foil is used as an electrode and a plastic film such as polyethylene, polypropylene, polystyrene or polycarbonate is stacked from both ends and wound into a cylindrical shape. According to the type of plastic film, it is also called polyethyl capacitor, polypropylene capacitor, polystyrene capacitor and polycarbonate capacitor.

The filter film capacitor refers to an energy storage device installed at both ends of the rectifier circuit to reduce the AC ripple ripple coefficient and improve the smooth DC output. The filter circuit requires the storage capacitor to have a large capacitance. In all circuits that need to convert AC power to DC power, setting the filter film capacitor will make the performance of the electronic circuit more stable, and also reduce the interference of the alternating ripple ripple on the electronic circuit.

The sign of the filter film capacitor in the circuit is generally denoted by C, and the capacitance should be determined according to the load resistance and the output current. The higher the power supply voltage U, the larger the charge q of the capacitor. When the filter film capacitance reaches a certain capacity, increasing the capacitance of the capacitor may adversely affect other indicators.

The filter film capacitor is an energy storage device connected in parallel to the output end of the rectifier power supply circuit to reduce the AC ripple ripple coefficient and smooth the DC output. In the electronic circuit that converts AC to DC power, the filter film capacitor not only makes the DC output of the power supply smooth and stable, but also reduces the influence of the alternating ripple current on the electronic circuit, and also absorbs the current fluctuations generated during the operation of the electronic circuit. The interference of the AC power supply makes the performance of the electronic circuit more stable.

In order to obtain a good filtering effect, the capacitor discharge needs to be slow, and the slower the capacitor discharge, the smoother the output voltage and the better the filtering effect. The speed of capacitor discharge is related to the capacity and load of the capacitor. The larger the capacity and load, the slower the capacitor discharge. At the same time, the capacitance of the selected filter film capacitor in the filter circuit is relatively large, but in the case of tens of kilohertz or even higher frequencies, the requirement of the frequency characteristics is much more important than the requirement of the capacity.