Why Is There a Ferrite Lump on Your Charging Cable?

Ashley | 02 - 27 - 2021
Charging Cable

Have you noticed the bulky black box attached to the charging cord of any laptop or mobile? What is the black box on a power cord called? It is generally called ferrite beads or ferrite cords that help increase efficiency while charging mobile phones or other devices. This article will tell you everything about the power cords and the ferrite beads. 

You can also find these ferrite beads in the laptop charger and the printer, keyboard, and mouse wire. 

Are Ferrite Beads Necessary? 

Usually, the electrical current passes through the cable wire to power up any device. The electric current in the cable creates radio energy within itself and emits waves outside the cable.

What Is the Black Box on a Power Cord Called?
  • A. Ferrite Cord
  • B. Ferrite Beads
  • C. Ferrite Chokes
  • D. All of the Above

This cable receives and transmits signals from nearby gadgets that have the same capability. Therefore, if you remove the ferrite bead from the cable, other power sources might use the electrical power and hinders the actual device. If any devices result in noisy signals such as radio, they might interfere and lead to distorted voice.

Hence, it stops energy transmission EMI and interferes and stops other signals from cell phones and other nearby power sources. 

What is the box on a power cord called? These cylinders contain something called ‘ferrite beads’ or ‘ferrite chokes,’ which are explicitly kept inside the casings to eliminate energy loss in the cord. These are widely known as EMI filters or chokes used to make charging and power transfer more efficient. 

If the current passes through the cable, there might be a large energy loss through electromagnetic interference(EMI). Ferrite beads are mostly kept near the ends of cables, which is the source. The ferrite ceramic present in each of these cylinders absorbs high-frequency electromagnetic noise. 

If you open the plastic cylinder, you can find the ferrite ceramic cylinder in two halves. The ferrite bead presented in the charger can block radio waves’ emission from the cable so that only the appropriate device can take in all the power. 

Charging cable and ferrite cylinder together form ferrite lump for the charger. Ferrite beads are one of the least expensive types of interference filters. A simple ferrite ring has insulated wire wrapped around a magnetic material. 


  • The ferrite beads can stop the use of unwanted use of energy. 
  • These cylinders can prevent noisy signals in other nearby devices.
  • They also help to charge more efficiently.

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