What is a Common Mode Choke?

The most concise summary is that in a common mode choke configuration, the currents travel in the same direction creating a magnetic flux that counters noise by adding to it.

As you may have already thought, the name common mode choke is not a coincidence. “Choke” relates to the process of blocking the unwanted noise or frequency. When it comes to different products or uses, the common mode choke is used in electronics and electro-mechanical devices such as antennas, wiring harnesses, generators, motors, and various resistive loads.

In fact, single-line, single-phase wiring with a common mode choke configuration is the most standard type of wiring in residential homes.

What are common mode choke uses?

When there is electromagnetic interference, a common-mode choke or filter serves as an electrical device that blocks high-frequency noise, such as unwanted radio signals and unshielded electronics, while allowing low-frequency current to pass.

What is electromagnetic interference or mode noise?

Electromagnetic interference in electrical circuits can take the form of differential mode noise or common mode noise. In differential mode noise, the current flows in the line, and input sides run in opposite directions. Common mode noise occurs when the current flows in the line and input sides enter and exit in the same direction, returning through a common ground. Both types of magnetic interference happen when transmissions do not generate magnetic fields that are equal and/or cancel each other out.

What makes the common node different from normal and differential mode?

In a common-mode configuration, the currents travel in the same direction. This creates a magnetic flux that counters noise by adding to it. In normal or differential mode, current travels through a conductor from the source to the load and then back again on the return line that completes the circuit. Common mode current refers to electrical noise that travels on both conductors simultaneously.

Advancements in noise suppression.

Modern chokes are more efficient and consolidated than more aged examples. They use crystalline cores, which are 8-10 times more useful than ferromagnetic and ferrite cores. Crystalline cores also have a more elevated frequency range, reaching up to 300 Hz. These updates are important because EMI noise suppression increases when technicians use chokes with crystalline cores compared to traditional models.

Where can you get ISO Certified Common mode chokes?

We’re proud to be ISO 9001:2015 certified for meeting the most stringent standards, and we strive to make our clients happy by offering efficient operation and high-quality products. Amgis offers a variety of standard high efficiency common mode chokes.

For more information on our Common Mode Choke Series or to request a custom quote, visit our product page.