Is that the positive wire is twisted with the negative wire ?? , as in this figure , Does The effect exist if we do not do so ?
http://www.littlewhitedog.com/images/reviews/other/00009/568a_normal.gif
2007-05-02 16:27:42 · 2 answers · asked by andrew martin 1 in Computers & Internet ➔ Computer Networking
Twisted pair
From Wikipedia, the free encyclopedia
http://en.wikipedia.org/wiki/Twisted_pair
Twisted pair cabling is a form of wiring in which two conductors are wound together for the purposes of canceling out electromagnetic interference (EMI) from external sources and crosstalk from neighboring wires.
Twisting wires decreases interference because the loop area between the wires (which determines the magnetic coupling into the signal) is reduced. In balanced pair operation, the two wires typically carry equal and opposite signals (differential mode) which are combined by subtraction at the destination. The noise from the two wires cancel each other in this subtraction because the two wires have been exposed to similar EMI.
The twist rate (usually defined in twists per metre) makes up part of the specification for a given type of cable. The greater the number of twists, the greater the attenuation of crosstalk. Where pairs are not twisted, as in most residential interior telephone wiring, one member of the pair may be closer to the source than the other, and thus exposed to slightly different induced EMF.
2007-05-02 16:53:03 · answer #1 · answered by Anonymous · 0⤊ 0⤋
the twists in twisted pair create managetic fields which are 180 degrees out of phase with the adjacent pairs canceling out the effects of EMI. remember that each pair of wire is twisted then all four pairs are also twisted
2007-05-02 16:49:17 · answer #2 · answered by lv_consultant 7 · 0⤊ 0⤋