To know why electrolytic capacitors explode, you first need to know what electrolytic capacitors are. An electrolytic capacitor is a kind of capacitor. The metal foil is a positive electrode (aluminum or tantalum), the oxide film (aluminum oxide or tantalum pentoxide) which is in close contact with the positive electrode is a dielectric, and the cathode is made of a conductive material or an electrolyte (the electrolyte may be a liquid or Solid) is composed of other materials. Since the electrolyte is the main part of the cathode, the electrolytic capacitor is named after it. At the same time, the electrolytic capacitors are not connected correctly. Aluminum electrolytic capacitors can be divided into four categories: lead-type aluminum electrolytic capacitors; snap-in aluminum electrolytic capacitors; screw-type aluminum electrolytic capacitors; solid aluminum electrolytic capacitors.
Application of electrolytic capacitor
Polar electrolytic capacitors usually function as power supply filtering, decoupling, signal coupling, time constant setting, and DC blocking in power supply circuits or intermediate frequency and low frequency circuits. Generally, it can not be used in the AC power supply circuit. When used as a filter capacitor in the DC power supply circuit, the anode (positive electrode) should be connected to the positive terminal of the power supply voltage, and the cathode (negative electrode) should be connected to the negative terminal of the power supply voltage. Otherwise the capacitor will be damaged.
Non-polar electrolytic capacitors are commonly used in speaker divider circuits, television S correction circuits, and starter circuits for unidirectional motors.
Electrolytic capacitors are widely used in household appliances and various electronic products. Their capacities range from 1 to 33000 μF and rated operating voltages range from 6.3 to 700V. The disadvantage is that the dielectric loss and the capacity error are large (the maximum allowable deviation is +100%, -20%), the high temperature resistance is poor, and the storage time is long and easy to be invalid.
The polarity of the electrolytic capacitor, pay attention to the "-" on the side of the electrolytic capacitor is the negative, "+" is the positive, if the electrolytic capacitor is not marked with positive and negative, it can also be judged according to the length of its pin, long feet It is the positive electrode and the short leg is the negative electrode.
The reason of Electrolytic capacitor explosion
1. Positive and negative poles are reversed
2. The actual use voltage is higher than the nominal withstand voltage of the electrolytic capacitor
3. The ripple in the circuit is too large
4. The use temperature is higher than the nominal value of the capacitor
5. The quality of the capacitor itself
6. After a long time of use, the electrolyte is reduced, dry, and caused by changes in capacitance parameters.