EMI Filter Fabrication

EMI Filter
Most electronics use an electromagnetic interference (EMI) filter to block signals or noise that can disrupt the device’s operation. If you need an EMI filter for a specific application, you may benefit from a custom solution from Captor Corp. We provide design and fabrication services to develop custom EMI filters based on our clients’ unique requirements.

Overview of Our EMI Filter Design & Fabrication Capabilities

At Captor Corp., we have the resources and expertise needed to design and fabricate top-quality EMI filters more cost-effectively than our competitors. The following are some of our specific capabilities:

  • General Capabilities: Custom design and build-to-print
  • Process: We can take you from prototyping and engineering to manufacturing and testing
  • Equipment: Automated or manual
  • Components: Capacitors, inductors, relays, resistors, chokes, diodes, varistors
  • Termination Interfaces: Solder terminals, threaded terminals, connectors, wire harnesses, wire leads
  • Protection: Circuit, transient voltage, HEMP/EMP
  • Insertion Loss: 1000 VDC for line-to-line and line-to-chassis / 0 to 100 dB
  • Voltage Drop: Less than 1% of the rated voltage
  • Voltage Rating: 0 to 400 VDC and 0 to 480 VAC, with higher voltage ratings available upon request
  • Current: 0 to 400 amps, with higher current ratings available upon request
  • Frequency: DC to 400 Hz, with other frequencies available upon request
  • Typical Operating Temperature Range: -55 °C to 71 °C
  • Typical Storage Temperature: -55 °C to +105 °C
  • Standards: MIL-STD-202, MIL-STD-220, MIL-STD-461, MIL-PRF-15733
  • Configurations: Single L, Double L, Single Pi, Double Pi
  • Testing: Altitude, temperature cycling, shock, electrical, vibration, environmental, mechanical

Visit our custom EMI filters page to learn more.

Types of EMI Filters We Fabricate

Depending on each client’s needs, we offer design and fabrication services for a range of EMI products, including EMI filters for power supplies. Our past projects have included custom EMI filters with tight tolerances to fit specific systems.

Some of our past EMI filter designs include:

  • Custom EMI Filters: We have developed more than 10,000 custom EMI filter designs based on our clients’ specific needs in the commercial, aerospace, military, and industrial sectors.
  • Military EMI Filters: Our line of military EMI filters has provided clients with reliable solutions for military and aerospace applications. We fabricate custom filters as well as standardized COTS-MIL EMI filters in compliance with MIL-STD-461 and RTCA/DO-160 regulations.
  • DC EMI Filters: These standard filters are among our core offerings, and we manufacture them according to MIL-PRF-15733. They are rated from 0 to 400 VDC and 1 A to 25 A.
  • Shielded-Facility Room EMI Filters: Some facilities require radiofrequency (RF) shielding EMI filters to protect them from electromagnetic disturbances or external electromagnetic interference. Our solutions offer sufficient protection in these environments, which include secured areas and shielded rooms.

Past EMI Filter Fabrication Project Highlights

One of our clients required a reliable EMI filter to meet the needs of a particular application for aerospace and military use. Through our expertise and in-house services, we provided this client with a solution that met the project’s unique specifications.


This client needed a specific filter for handling DC and AC power and signal lines in a systems application intended for both military and aerospace use.


The client was aware of our expertise in electromagnetic interference, so they reached out to us for custom EMI filter design and fabrication. Working with the customer, we fabricated a filter with operating voltages and currents of:

  • 115 VAC, 3-phase, 400 Hz, 4 amps
  • 270 VDC, 12 amps, 2 lines
  • 5 VDC, 500 mA for 14 signal lines

The filter was 7.00” x 4.00” x 5.00” with a weight of 6 pounds. Its operating temperature was -55 °C to +105 °C, while its non-operating temperature was -55 °C to +125 °C. It also featured an M24308 military D-sub connector output termination and a D38999 military connector input termination. The chassis consisted of cold-rolled steel and an electro tin-lead plated finish, as well as threaded inserts for mounting. To ensure optimal performance, we conducted environmental and electrical testing.

Details & Specs

Other specs of our custom solution were as follows:

  • Capabilities: Filters AC and DC power lines as well as signal lines for the designated application
  • Electrical Testing Performed:
  • Insertion loss
  • DWV
  • Insulation resistance
  • Capacitance
  • Voltage drop
  • Burn-in at rated current and voltage
  • Environmental Testing Performed:
  • Vibration
  • Shock
  • Thermal shock and cycling
  • Humidity
  • Altitude
  • Standards Met:
  • MIL-STD-461
  • Customer supplied specification
  • AS9100 quality system
  • ANSI/IPC-A-610 Class 3 workmanship
  • Captor Corporation for EMI Filter Fabrication

    EMI filters are essential components in every electrical and electronic device. Based on your EMI device and specifications, Captor Corp can help design and fabricate an ideal custom EMI filter. To learn more about our capabilities and offerings, contact us today or request a quote.