What is the capacitance change rate with time of cbb21 - film capacitor?

As a supplier of CBB21-film capacitors, I've received numerous inquiries about the capacitance change rate with time of these components. This topic is crucial for understanding the long - term performance and reliability of CBB21-film capacitors, which are widely used in various electronic applications.

Understanding CBB21-Film Capacitors

CBB21-film capacitors are metalized polypropylene film capacitors. They are known for their excellent electrical characteristics, such as low loss, high insulation resistance, and good self - healing properties. These features make them suitable for a wide range of applications, including power supplies, lighting circuits, and motor run applications.

The capacitance of a capacitor is a measure of its ability to store electrical charge. For CBB21-film capacitors, the initial capacitance is specified by the manufacturer and is typically measured under standard test conditions. However, over time, the capacitance of these capacitors can change due to various factors.

Factors Affecting the Capacitance Change Rate

Temperature

Temperature is one of the most significant factors influencing the capacitance change rate of CBB21-film capacitors. Polypropylene film, the dielectric material used in these capacitors, has a temperature coefficient of capacitance. As the temperature increases, the molecular structure of the polypropylene film expands, which can lead to a decrease in capacitance. Conversely, at lower temperatures, the film contracts, and the capacitance may increase slightly.

The temperature coefficient of capacitance for CBB21-film capacitors is usually in the range of - 20 to + 20 ppm/°C. This means that for every degree Celsius change in temperature, the capacitance can change by a few parts per million. For example, if a capacitor has an initial capacitance of 1 μF and a temperature coefficient of - 10 ppm/°C, a 10°C increase in temperature would result in a capacitance change of approximately - 0.1 nF.

Voltage

The applied voltage also affects the capacitance of CBB21-film capacitors. When a voltage is applied across the capacitor, the electric field within the dielectric material can cause a slight distortion of the molecular structure. This phenomenon, known as the voltage coefficient of capacitance, can lead to a decrease in capacitance as the applied voltage increases.

For CBB21-film capacitors, the voltage coefficient of capacitance is relatively small compared to some other types of capacitors. However, in high - voltage applications, it can still have a noticeable impact on the capacitance over time. For instance, if a capacitor is rated for 400V and is continuously operated at a high voltage close to its rating, the capacitance may gradually decrease over the course of its operation. You can find more information about our CBB21-Film Capacitor 400V on our website.

Aging

Aging is another important factor that causes the capacitance of CBB21-film capacitors to change over time. During normal operation, the dielectric material in the capacitor undergoes a slow degradation process. This can be due to factors such as oxidation, moisture absorption, and the accumulation of electrical stress.

As the dielectric ages, its ability to store charge may change, resulting in a gradual decrease in capacitance. The aging rate of CBB21-film capacitors is typically specified by the manufacturer in terms of the capacitance change over a certain period of time under specific operating conditions. For example, a capacitor may be guaranteed to have a capacitance change of less than ± 3% over 1000 hours of operation at a specified temperature and voltage.

Humidity

Humidity can also have an impact on the capacitance change rate of CBB21-film capacitors. Moisture can penetrate the capacitor's encapsulation and affect the dielectric material. This can lead to an increase in the dielectric constant of the polypropylene film, which in turn can cause an increase in capacitance. In addition, moisture can also accelerate the aging process of the dielectric, leading to more significant capacitance changes over time.

Measuring the Capacitance Change Rate

To accurately measure the capacitance change rate of CBB21-film capacitors, specialized test equipment is required. A capacitance meter can be used to measure the capacitance of the capacitor at different time intervals. The capacitor should be tested under controlled conditions, including temperature, voltage, and humidity, to ensure accurate results.

Typically, a long - term aging test is conducted to measure the capacitance change rate over an extended period of time. During this test, the capacitor is subjected to a constant voltage and temperature, and its capacitance is measured at regular intervals. The results of these tests can be used to determine the aging characteristics of the capacitor and to predict its long - term performance.

Importance of Understanding the Capacitance Change Rate

Understanding the capacitance change rate of CBB21-film capacitors is essential for several reasons. In electronic circuits, the capacitance of a capacitor often plays a critical role in determining the circuit's performance. For example, in a resonant circuit, a small change in capacitance can significantly affect the resonant frequency.

In power supply applications, the capacitance of the input and output capacitors can affect the filtering performance and the stability of the power supply. If the capacitance of these capacitors changes over time, it can lead to increased ripple voltage, reduced efficiency, and even circuit malfunction.

Our CBB21-Film Capacitor Offerings

At our company, we offer a wide range of CBB21-film capacitors with different voltage ratings and capacitance values. Our CBB21-Film Capacitor 200V is suitable for applications where a lower voltage is required, such as in some consumer electronics. The CBB21-Film Capacitor 160V is also a popular choice for applications with specific voltage requirements.

We ensure that our CBB21-film capacitors are manufactured using high - quality materials and advanced production processes. This helps to minimize the capacitance change rate and ensure the long - term reliability of our products. Our capacitors are also tested rigorously to meet international standards and customer requirements.

Contact Us for Procurement

If you are interested in purchasing CBB21-film capacitors or have any questions about their capacitance change rate and performance, please feel free to contact us. We are always ready to provide you with detailed product information and technical support. Our team of experts can help you select the right capacitors for your specific applications and ensure that you get the best value for your investment.

References

• Manufacturer's datasheets for CBB21-film capacitors
• Technical literature on the electrical properties of polypropylene film dielectrics
• Research papers on the aging and performance of film capacitors