what this? and what is the use of it!

[karthickb3e]

hi all....


i have doubt about the attached images... that there is small solid cylindrical item before the connectors or end of the cable.......i have been seen this in many cables...
please tell me what is the use of this.. and what this?

 

[chuckey]

They are bits of ferrite. These act on the cables so inductance is added to the cables. This appears as an impedance in series with each conductor and stops interference travelling down the cable.
Frank

 

[karthickb3e]

thank you chuckey.. to know the technology of reducing EMI using ferrite beads

 

[Tahmid]

Also in some circuits (especially power supplies), the "cylinder" consists of a capacitor which acts as a filter.

You may also find this helpful (page 4): www.pericom.com/pdf/applications/AN011.pdf

Hope this helps.
Tahmid.