The use of electrolytic capacitors

1. The DC electrolytic capacitor is polar: The polarity of the capacitor is marked on the base of the capacitor so as not to cause a short circuit or damage to the capacitor due to polarity. Use a bipolar electrolytic capacitor when you want to use a non-fixed polarity or use an indefinite circuit. Note that DC electrolytic capacitors cannot be used for AC.

2. Do not use the voltage higher than the rated voltage: if the voltage is higher than the rated voltage, the leakage current will increase and the capacitor may be damaged. The recommended working voltage is 70%-80% of the rated voltage. Capacitor use at the recommended working voltage will prolong the life of the capacitor.

3. Do not pass excessive ripple current through the capacitor: When the ripple current exceeds the rated value, the capacitor body will overheat, the capacity will decrease, and the capacitor lifetime will be shortened. The peak value of the applied ripple voltage should be less than the rated operating voltage.

4. The working environment temperature range is appropriate: the characteristics of the capacitor change with the operating temperature, in the case of higher temperature, capacity, leakage current increases, loss decreases; in the case of low temperature, capacity and leakage current drop, loss Increase. The use of capacitors at lower temperatures can increase the life. According to scientific statistics, the service life is doubled for every 10°C drop in ambient temperature.

5. Check the working frequency: The capacitance of the electrolytic capacitor is usually measured at a frequency of 100~120Hz. However, the capacity will decrease as the frequency increases, the loss increases as the frequency increases, and the ambient temperature rises.

6. Long-term storage of capacitors: The use of a rated DC voltage before processing for a long time to store, in fact, does not have much effect on the capacity and loss of the capacitor, but will cause the leakage current of the capacitor to increase and the withstand voltage to decrease. For long-term capacitor handling, apply a DC voltage to the rated voltage gradually before use.

7. The shell and cathode end of the electrolytic capacitor are not insulated: the shell and cathode of the electrolytic capacitor are connected through the electrolyte. If the shell of the capacitor must be insulated from the line, insulation must be taken at the location where the capacitor is installed.

8. Do not apply excessive force to the terminals or leads of the electrolytic capacitor: Excessive force is applied to the terminals or leads. This pull will act on the inside of the capacitor. This may lead to breakage of the leads or splitting of the terminals, which in turn may cause internal capacitors. The destruction of the connection causes internal short-circuits, open circuits, or leakage currents in the capacitor to rise, causing damage to the capacitor. When the capacitor is soldered to the circuit board, do not strongly shake the capacitor.

9. Pay attention to the temperature and duration when welding: The soldering iron should be kept at a distance from the plastic sleeve of the capacitor. When the capacitor is immersed in the solder bath, it is recommended that the temperature be within 260C for less than 10 seconds to avoid damaging the capacitor. The plastic sleeve may be broken or shrunk due to excessive welding time and high temperature.

10. Layout of holes on printed circuit boards: When designing printed circuit boards, the mounting pitch should be equal to the lead pitch. When the pitch is larger or smaller than the lead pitch, when the capacitors are installed, stress will be applied to the leads, which may cause Short circuit, circuit damage, leakage current increases.