1. Electrolytic capacitors have positive and negative polarities, so they cannot be reversed when used in a circuit. In the power supply circuit, when the positive voltage is output, the positive pole of the electrolytic capacitor is connected to the output end of the power supply, the negative pole is grounded, and when the negative voltage is output, the negative pole is connected to the output end, and the positive pole is grounded. When the polarity of the filter capacitor in the power circuit is reversed, the filtering effect of the capacitor is greatly reduced. On the one hand, the output voltage fluctuation of the power supply is caused, and on the other hand, the electrolytic capacitor corresponding to a resistor is heated due to the reverse energization. When the reverse voltage exceeds a certain value, the reverse leakage resistance of the capacitor will become very small, so that the power supply will work shortly, and the capacitor will be broken due to overheating.
2. The voltage applied to the two ends of the electrolytic capacitor should not exceed the allowable working voltage. When designing the actual circuit, a certain amount of margin should be left according to the specific conditions. When designing the filter capacitor of the regulated power supply, if the AC power supply voltage is 220~ When the secondary rectification voltage of the transformer can reach 22V, the electrolytic capacitor with a withstand voltage of 25V can generally meet the requirements. However, if the AC power supply voltage fluctuates greatly and may rise above 250V, it is best to select an electrolytic capacitor with a withstand voltage of 30V or higher.
3. The electrolytic capacitor should not be close to the high-power heating element in the circuit to prevent the electrolyte from accelerating due to heat.
4. For the signal with positive and negative polarity signal, two electrolytic capacitors can be used in series with the same polarity as a non-polarity capacitor.