If I am correct in assuming a twisted pair cable is used to provide reduced susceptibility to noise. What is the benefit in having the cable twisted when it is inside a foil screen/shield? Would shielding around two cables provide noise immunity regardless of whether the cables were twisted or not?

Thank you for any assistance in advance. I am relatively new to this topic so if anyone knew of any good reading materials to help it would be much appreciated.


1 Answer 1


A shield usually makes a pretty good protector against electric field disturbances (half the story) but, unfortunately, makes a pretty poor protection against magnetically coupled noise (the other half of the story).

Twisting the conductors in a pair mainly ensures that induced voltages (due to external magnetic disturbances) are equalized on both conductors thus, their effect can be defeated with a properly designed balanced receiver circuit.


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