474PSB700K2H

Film Capacitors

Film capacitors, also known as plastic film capacitors, are constructed using layers of plastic film and aluminium foil electrodes that are stacked together. They are constructed by winding the plastic film around an aluminium rod or mandrel. The plastic film has a dielectric constant that defines its capacitance value, and due to their ability to maintain high capacitance values and a very stable dielectric constant, they are widely used in a variety of applications and industries. This article will focus on the application field and working principle of a specific film capacitor called the 474PSB700K2H.

Application Field

The 474PSB700K2H is a high voltage capacitor designed for an operating voltage of 479.6V AC and a temperature range of -40°C to +85°C. It is used in a variety of applications, including electronic ballast circuits, AC motor run induction, TFT/LCD driving circuits, and PFC circuits. Its rated voltage, capacitance, and tolerance meet the latest European Standard EN 60252-1.

The 474PSB700K2H is a metallized film capacitor which has low leakage, low dissipation factor, high insulation resistance, and an excellent self-healing effect. Its construction techniques, combined with a tight winding structure, reduce noise, and make it suitable for use in electronic ballast circuits with minimum radiated noise. It is also designed with an internal arcing extinction voltage (EAF), which automatically disconnects it from the voltage source in case of an arcing fault.

The 474PSB700K2H is also a reliable, robust, and cost-effective choice for applications such as AC motor run induction, TFT/LCD driving circuits, and PFC circuits. It delays the start-up of luminaires, reduces inductive flyback noise across the rectifier bridge, and is suitable for electrolytic capacitors due to its low ESR and low start-up current. In PFC circuits, the 474PSB700K2H has low ESR, high current capacity, and high withstand voltage which allows it to safely and reliably power devices with large current fluctuations.

Working Principle

The 474PSB700K2H is a metallized film capacitor, which means that it has an electrode layer that is formed on the surface of a polymer film instead of a solid metal conductor. The aluminum or zinc layer creates a shielding barrier that inhibits current from crossing the metal and polymer layers. Due to its construction, this type of capacitor has a low equivalent series resistance (ESR), which helps assure that energy is not lost in the form of heat during operation.

The working principle of the 474PSB700K2H is based on the principle that when opposite charges accumulate on the two sides of an insulating material, a current can flow through the material when a voltage is applied. This current can be controlled by the capacitance of the device, which is the ratio of the charge on each side of the dielectric material. The 474PSB700K2H is designed to have a very stable capacitance at temperatures ranging from -40°C to +85°C and at frequencies of up to 60kHz.

The metallized film of the 474PSB700K2H also plays a role in its self-healing performance. When subjected to high surge currents, the metal film may burn and create a pocket of gas, which is then caught within the insulating material. This gas pocket is then able to conduct current, which increases the capacitance of the device and causes it to self-heal. This self-healing capability is invaluable in areas such as filtering and power conversion, where the device is subjected to high levels of noise and arcing.

Conclusion

The 474PSB700K2H is a high voltage film capacitor designed to be used in a wide range of applications, including electronic ballast circuits, AC motor run induction, and PFC circuits. It is constructed with metallized film and has very low ESR, high capacitance, and an excellent self-healing effect. This makes it an excellent choice for applications that require reliable operation with minimal noise and arcing. The 474PSB700K2H, and other film capacitors, will continue to be essential components in a variety of applications.