When the polarity of the filter capacitor in the power circuit is reversed, the filtering effect due to the capacitor is greatly reduced. On the one hand cause fluctuations in the power output voltage, on the other hand due to reverse power so that at this time is equivalent to a resistor electrolytic capacitor heating. When the reverse voltage exceeds a certain value, the capacitance of the reverse leakage resistance will become very small, so energized work soon, you can make the capacitor due to overheating and blasting damage.
2. Plus the voltage across the electrolytic capacitor can not exceed the allowable operating voltage, the actual circuit design should be based on the specific circumstances leaving a margin, when the design of the filter capacitor power supply, if the AC power supply voltage is 220 ~ Transformer secondary rectified voltage up to 22V, PCB proofing at this time choose to withstand 25V electrolytic capacitors generally meet the requirements. However, if the AC power supply voltage fluctuations and may rise to 250V or more, the best choice of voltage 30V electrolytic capacitors.
3. Electrolytic capacitors in the circuit should not be close to high-power heating elements, to prevent accelerated heating and drying of the electrolyte.
4. For positive and negative signal filtering, two electrolytic capacitors can be taken in the same polarity series, as a non-polar capacitor.
5. Capacitor housing, auxiliary leads and positive, negative and circuit boards must be completely isolated.