What is a feedthrough capacitor? Type of feedthrough capacitor?

The through-core capacitor, because it is coated with a metal layer on the porcelain tube, forming two poles inside and outside. Because the tube is empty, it is called a feedthrough capacitor. It is a three-terminal capacitor, but compared with ordinary three-terminal capacitors, because it is directly mounted on the metal panel, its grounding inductance is smaller, and there is almost no influence of lead inductance. In addition, its input and output terminals are The metal plate is isolated to eliminate high frequency coupling. These two characteristics determine that the through-core capacitor has a filtering effect close to the ideal capacitor. Moreover, it is an ideal device for interference filtering.

Feedthrough capacitors (also known as feed-through filters, low-pass filters, EMI filters) are called electromagnetic interference filters, and they are a new type of component that has been popularized and applied in recent years. It can effectively suppress grid noise, improve the anti-interference ability of electronic equipment and the reliability of the system, and can be widely used in electronic measuring instruments, computer room equipment, switching power supplies, measurement and control systems and other fields.

1. Type C

This is a low self-induction device that avoids high-frequency noise interference to the ground. It has a low cost and is suitable for applications with high impedance sources and high loads.

2. L type

This is a through-core capacitor with inductive and capacitive components. This type of capacitor is typically used in circuits with low impedance sources and high impedance loads, and vice versa. Note: the inductive component should face the low impedance source

3. Pi type

The Pi type is composed of two capacitive elements and an inductive element between the two capacitive elements, and exhibits low impedance to both the impedance source and the load. Pi type filter provides better high frequency filtering performance than C type and L type structure

Features and applications
1) Welded through-core capacitor

Welded through-core capacitors are the most ideal product for tight installation space;

Application: Mainly used for filtering signals, data lines and AC power lines;

Telecommunications equipment, transmission equipment, microwave filters, industrial computers, composite circuit filter components;

Small size: effective use of space;

Rated voltage: up to 1000VDC;

Various circuit structures: C-type, Pi-type and L-type circuits are all available;

High temperature structure: can prevent backflow during installation;

Certification: available for MIL-F-15733 QPL and MIL-C-11015 (CK99) certified filters;

2) Resin sealed threaded through-core capacitor

Nuts and washers for resin-sealed bolt-through capacitors can be easily installed in the through hole position;

The two ends of the solid shell are sealed with resin to provide good environmental protection;

Application: Mainly used for signal, data line, DC power line filtering; among them, micro-extrusion mounting or screw mounting is the ideal choice when welding is not suitable, suitable for microwave and other high-frequency applications;

Voltage: up to 2500VDC/240VAC

Certification: Available for MIL-F-15733 certified products

Circuit structure: C type, L type, Pi type

3) High current and high voltage resin sealed through-core capacitor

Application: High-current filters are mainly used in high-current switching power supplies and DC charging systems;

High-voltage filters are mainly used in high-voltage power supplies, and are easy to install with a solid bolt structure;

Features: high current up to 100Amps

Voltage: up to 2500VDC and 240VAC@400HZ