What are these Tiny Cylinder in Power Cords & Cable & Why?

The tiny cylinders in power cords and cables are referred to as ferrite cores (or) ferrite beads. These cylindrical components are constructed of ferrite, a magnetic ceramic.

Ferrite cores (or) beads serve two primary functions in power connections and cables:

1). Eliminating electromagnetic interference (EMI): Power cords & cables can operate as antennas, taking up or emitting interference signals. Ferrite cores effectively suppress high-frequency electromagnetic interference through providing an impedance to undesirable signals. The ferrite substance absorbs & dissipates the high-frequency energy, preventing it from traveling through the cable and interfering with surrounding electronic devices.

2). Reduces radio frequency interference (RFI): Ferrite cores can prevent RFI from traveling along the cable. RFI may be generated by electronic circuits (or) components in linked equipment, and it has the ability to interfere with other devices and systems. Ferrite cores reduce interference by providing a high impedance to radio frequencies.

Ferrite cores are often clamped or snapped onto power cords or cables, encapsulating the conductors within the ferrite substance. The efficiency of the ferrite core in reducing EMI and RFI is determined by factors such as material composition, size, & number of turns in the cable.

Ferrite cores are often found in power cords for

  • Computers,
  • Audio/video equipment, &
  • Various other electronic devices,

as well as in various types of cables such as network, audio/video, and instrumentation. They contribute to comply with electromagnetic compatibility (EMC) rules and limit the possibility of interference between electronic devices & systems.

It’s essential to understand that ferrite cores are passive components that don’t need any additional power or connections. They work by utilizing the magnetic characteristics of the ferrite material to reduce unwanted electromagnetic & radio frequency interference.

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