Cautions While Usage Capacitors
- Normally, values higher than the rated voltage may cause a breakdown of the capacitor dielectric and damage the capacitor. Metallized capacitors have self-healing properties and the application of voltages higher than rated voltage will not cause an immediate short circuit. But the insulation resistance will drop with the charge time goes on, the leak current will increase gradually. The capacitor may lead to smoke or fire due to the heat produced and the breakdown of the capacitor
- If a capacitor marked D.C. is used as an A.C. capacitor, the maximum working voltage is limited by the heat produced or by discharges. The maximum working voltage converted to AC voltage depends on different types of the capacitors. For more details, please contact us.
- When a capacitor is used at high frequency, the self-healing may cause breakdown of the capacitor due to the aging of the dielectric. So the rated voltage should be decreased at high frequency. And also, the ambient temperature and the self-temperature rise should both be taken into account. If the capacitor is subject to rms or pulse currents higher than those admitted, make sure the operating temperature (ambient temperature plus self-temperature rise) will not exceed the rated upper temperature.
- The capacitor has a large charge and discharge current due to the low internal impedance of it. The capacitor will deteriorate and breakdown when the current exceeds the permissible value. The permissible current can be categorized into pulse current (peak value) and continuous current (rms value) depending on different breakdown style. Make sure the operating current does not exceed the permissible value.
- Generally, the permissible pulse current is the product of dv/dt and the capacitance. The permissible rms current varies with dielectric, operating frequency and end spray.