Pay attention to these parameters when purchasing capacitors

When we purchase products, we can only see the appearance through the visual observation of the eyes. Whether the performance of the products and the materials used meet their own needs, these are not visible. Then this time you need to look at the parameters, the parameters can indicate the performance, materials, life and so on of this product, so it is very important to look at the parameter selection, the capacitor is also the same, you must pay attention to the following parameters when purchasing.

1. Nominal capacitance: The capacitance value determined by the capacitor design and usually indicated on the capacitor.

2. Capacity deviation: The allowable deviation of the nominal capacitance.

3. Lower category temperature: The low ambient temperature determined by the capacitor design for continuous operation.

4. Upper Limit Category Temperature: The high ambient temperature as determined by the capacitor design for continuous operation.

5. Rated temperature: The high ambient temperature at which the rated voltage can be continuously applied.

6. Rated voltage: The peak value of a large DC voltage or pulse voltage that can be continuously applied to the capacitor at any temperature between the lower category temperature and the rated temperature.

7. Category voltage: The high voltage that the capacitor can continuously apply to the capacitor at the upper category temperature.

8. Temperature derating voltage: A high voltage that can be continuously applied to the capacitor at any temperature between the rated temperature and the upper category temperature.

9. Climatic category: The high voltage that can be continuously applied to the capacitor at any temperature between the climatic category temperatures to which the capacitor belongs. (IEC60068-1 standard: such as 55/85/21). One number represents the lower category temperature, two numbers represent the upper category temperature, and the third number represents the number of days of steady state damp heat.

10. Capacitor temperature coefficient: The rate of change of capacitance measured with temperature over a specified temperature range.

11. Loss tangent: the power loss of the capacitor divided by the reactive power of the capacitor at a sinusoidal voltage of the specified frequency

12. Insulation Resistance / Time Constant: The insulation resistance is the ratio of the DC voltage applied after one minute of charging of the capacitor to the value of the leakage current flowing through the capacitor.

13. Pulse rise time: The pulse rise time indicates the ability of the capacitor to withstand the large current peaks caused by rapid voltage changes.

14. Self-healing: After partial breakdown of the dielectric of the capacitor, the electrical characteristics of the capacitor are rapidly and substantially restored to the value of the pre-breakdown value. (This is the performance of the film capacitor)

After we understand the basic meaning of the capacitor parameters above, we can choose the right capacitor according to our own requirements