The Application of Electrolytic Capacitors

Polarized electrolytic capacitors usually play roles such as power supply filtering, decoupling, signal coupling, time constant setting, and blocking direct current in power supply circuits or medium-frequency and low-frequency circuits. Generally, they cannot be used in alternating current power supply circuits. When used as filtering capacitors in direct current power supply circuits, the anode (positive terminal) of the capacitor should be connected to the positive terminal of the power supply voltage, and the cathode (negative terminal) should be connected to the negative terminal of the power supply voltage. It must not be connected in reverse; otherwise, the capacitor will be damaged.

Non-polarized electrolytic capacitors are usually used in speaker crossover circuits, the S correction circuits of televisions, and the starting circuits of single-phase motors.

Electrolytic capacitors are widely used in household appliances and various electronic products. Their capacitance range is relatively large, generally ranging from 1 to 33,000 μF, and the rated working voltage range is from 6.3 to 700V. Their disadvantages are that the dielectric loss and capacitance error are relatively large (the maximum allowable deviation is +100% and -20%), the resistance to high temperatures is poor, and they are prone to failure after being stored for a long time.

Regarding the polarity of electrolytic capacitors, please note that on the side of the electrolytic capacitor, the symbol "-" indicates the negative pole and the symbol "+" indicates the positive pole. If the positive and negative poles are not marked on the electrolytic capacitor, it can also be judged according to the length of its pins. The long pin is the positive pole, and the short pin is the negative pole.