Use of small cylindrical modules near the laptop charger


👤 Diwas Poudel    🕒 Jan 29 2022    📁 TECH

These small cylindrical-shaped bumps can be found not only in laptop charger cables, but also in other electronic devices such as printer cables, monitor cables, and various medical equipment such as MRI machines, CT Scan machines, and Xray machines. It is known by a variety of names, including ferrite beads, EMI filters, ferrite chokes Ferrite Core, Ferrite Ring, or Ferrite Block, etc. The primary goal is to reduce Electromagnetic Interface and Radio Frequency Interference entering the devices.

What is Ferrite Beads/ Ferrite Chokes?

Ferrite Beads are passive electric components containing iron material as the main part, which is why they are called ferrite. It is a semi-magnetic metal composed of rust (iron oxide) alloyed with other metals. This choke acts as a low pass filter, preventing unwanted radiofrequency energy from entering electronic devices.

They're simply wrapped around the charging cable. On the power supply, they are connected in series. Acts as a high impedance to noise and a low impedance to direct current. They are designed to have very high resistive at high frequency, In technical terminology, we called Ferrite beads are effective at filtering high-frequency differential mode noise. They are not complex circuits they are cylindrical hollow ferrous material as shown below.

ferrite-beads
fig. Ferrite Beads 

How Ferrite Works?

There are various types of electronics devices in our environment that operate at different frequencies, such as Wifi (2.4 GHz to 5 GHz), Mobile (850 MHZ - 900 MHZ), TV, Radio, Microwave Oven (2.45 GHz), Bluetooth, and Cordless Telephones. We also know that when electricity is passed through a cable, a magnetic field is created around it due to Faraday's law. When electricity is passed through a long cable, it acts as an antenna. And the antenna can both send and receive signals.

em-spectrum-orig
fig. frequencies used by different devices

In the case of cables, the antenna formed at the cable receives the incoming generated waves and distorts the actual signal flowing through the cables, and hardware equipment such as laptops receive noisy signals, which can damage your hardware.

So, small cylindrical bumps are wrapped around the laptop charger, and these beads act as a filter, preventing unwanted high-frequency noise signals from reaching the laptop. Ferrite beads reduce noise by absorbing unwanted noise and dissipating it as thermal energy, which we call heat. This heat causes ferrite magnetic loss.

What is the Major Function of Ferrite beads in laptops?

Here are some of the major functions of Ferrite beads in laptops:

1 Suppression of EMI
2 Improving Supply Decoupling
3 Reducing RF Coupling
4 Also to suppress voltage spikes due to noisy supply and irregular ac voltages.

Simply we can say Ferrite Beads helps to keep away cable from serving as a transmitting antenna and disrupting external electronics devices like speakers, mobile, etc. The second is to keep it away from acting as a receiving antenna and disrupting devices that are directly attached to it example: a laptop.

What is the Position of Ferrite in Cable?

They are attached at the end of the cable to supply healthy signals to the electrical equipment. As a result, when the ferrite beads reduce noise, the operating signals are received quickly by the electronics circuit.

Do all Ferrite Beads cut off the same range of Frequencies?

No, there are different types of ferrite beads with different cutoffs. For instance, nickel-zinc ferrite can suppress EMI from 20 to 250 MHz.

How do you choose the proper chip bead ferrite for you?

It varies depending on the application. Different applications may necessitate a different range of working frequencies and a different amount of attenuation.

Can I remove the ferrite bead from my laptop charger?

Ans: It is not advised to remove it from the laptop charger. If it is damaged, try to replace it by purchasing ferrite from the market. If you remove your ferrite bead, your laptop screen may flicker, and the speaker connected to your laptop may make noise because modern electronics are very sensitive to even small ac currents, among other things.

Is it possible to swap ferrite beads from one charger to another?

Ans: The ferrite beads in the CutOff laptop chargers are similar, thus there will be no issues. However, if ferrite from one type of electronics equipment is used in another, a problem may arise.

 

 

 

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