Feedthrough Capacitor

A feedthrough capacitor is a non-polar capacitor and a type of low-pass three-terminal filter. Its leads conduct axially, and the two electrodes (lead and housing) form a capacitor. Mounted on metal panels or covers, it has extremely low grounding inductance. As a passive component closest to an ideal  filter capacitor, it performs exceptionally well in suppressing high-frequency noise and signal filtering, and is a crucial and irreplaceable electronic component in EMI/EMC (Electromagnetic Interference/Electromagnetic Compatibility) applications.

Dielectric Materials of Feedthrough Capacitors

- Ceramic dielectric

- Film dielectric

Ceramic Dielectric Types (by Structure)

- Tubular type

- Solder type

- Threaded type

These types feature small sizes, making them more suitable for installation in narrow spaces.

Ceramic Dielectric Types (by Material)

- NP0 (C0G): Operating temperature range: -55℃ ~ +125℃

- SL, X7R: Operating temperature range: -55℃ ~ +125℃

- Y5P, Y5U, Y5V: Operating temperature range: -25℃ ~ +85℃

Circuit Structures

- Type C (single capacitor)

- Type LC (single capacitor + single inductor)

- Type T (inductors at both ends + capacitor in the middle)

- Type PI/π (capacitors at both ends + inductor in the middle)

Purpose: Filtering

Function: Filtering out interference signals

Working Principle: It utilizes the impedance characteristics of the capacitor to form a low-impedance path for high-frequency noise, bypassing the interference signals to the ground plane.

Application Fields

Smart home appliances, automotive electronics, medical equipment, automation equipment, instruments and meters, shielded rooms, information and communications, aerospace, etc.

Typical Application Scenarios

1. Power Supply Filtering

- Scenario: Input/output terminals of DC/DC or AC/DC modules.

- Function: Blocks common-mode and differential-mode noise on power lines to prevent external interference from entering sensitive circuits.

2.Signal Line Filtering

- Scenario: RF (Radio Frequency) signal lines, sensor signal lines.

- Function: Filters out high-frequency noise coupled to signal lines to prevent signal distortion.

3. Shield Grounding

- Scenario: Wire holes of metal enclosures and shielded cavities.

- Function: When cables pass through the shield, the feedthrough capacitor provides a low-impedance grounding path.

Applied Products and Equipment

- Consumer Products: High-end audio equipment, refrigerators, air conditioners, drones, cameras, chargers, etc.

- Industrial Products: Switching power supplies, PLC (Programmable Logic Controller) controllers, converters, inverters, frequency converters, servo drives, etc.

- Instruments and Meters: Pressure transmitters, oscilloscopes, spectrum analyzers, signal generators, sensors, etc.

- Communications Products: Base stations, RF modules, antenna systems, satellite communications, etc.

Kete Microwave Electronics Co., Ltd. specializes in designing,developing and manufacturing advanced RF/Microwave passive components. As a leading manufacturer Kete provides the primary products lines include ferrite components (RF Isolator, RF Circulator), High Power Resistive Components (RF Resistor, Coaxial Fixed Attenuators & Termination), Feed-through Capacitor (EMI RF Filter), Microwave Power Divider and RF Filter.