Feedthrough Capacitor

Feedthrough Capacitor Filter

2-1600A, 250VAC/1000VDC, DC/50/60Hz

What Are Feedthrough Capacitors

A feedthrough capacitor is a specialized passive electronic component designed to suppress high-frequency noise in circuits where conductors pass through shielded enclosures or panels. Its construction features a central conductor (feedthrough) encapsulated by dielectric material (e.g., ceramic X7R, NP0, or glass) and enclosed within a metal housing, creating a low-impedance path to ground for unwanted interference. Key specifications include capacitance values (1pF–10nF), voltage ratings (50V–1kV), and self-resonant frequency (SRF), with performance optimized for frequencies ranging from 1MHz to 6GHz. Unlike traditional capacitors, its near-zero lead inductance minimizes parasitic effects, ensuring effective noise filtering even in GHz-range applications.

What Are Feedthrough Capacitors Used For?

Feedthrough capacitors are critical in scenarios requiring precise isolation of high-frequency noise. In power electronics, they filter switching noise from DC/DC converters and inverters, preventing electromagnetic interference (EMI) propagation in electric vehicle charging systems and solar inverters. RF communication systems, such as 5G base stations and satellite transceivers, use them to decouple signal lines from shielded enclosures, maintaining signal integrity in multi-antenna arrays. Medical imaging equipment, including MRI machines, relies on these capacitors to block gradient coil noise from contaminating power supplies. Aerospace and defense applications deploy EMP-hardened variants to protect avionics and radar systems from high-altitude electromagnetic pulses (HEMP), while industrial automation integrates them into PLCs to suppress motor-driven noise in robotic assembly lines.

Types of Feedthrough Capacitors

Feedthrough capacitors are categorized by material composition, structural design, and operational resilience. Ceramic dielectric types employ multilayer ceramic technology for broad-frequency filtering in consumer electronics and IoT devices, balancing cost and miniaturization. Three-terminal configurations incorporate a dedicated ground terminal and π-filter topology to enhance attenuation bandwidth, making them suitable for military radios and precision oscilloscopes. EMP/HEMP-resistant models combine multilayer ceramic discs with transient voltage suppression (TVS) diodes, rated for surge voltages up to 10kV, and are mandatory in nuclear reactor control systems and battlefield communication gear. High-temperature/high-voltage variants utilize barium titanate-based dielectrics and hermetic sealing for operation in extreme environments, such as downhole drilling sensors (200°C) and spacecraft power distribution units. Hybrid designs also exist, merging feedthrough capacitors with ferrite beads for multi-stage filtering in hybrid electric vehicle battery management systems.