coaxial cable?????????????
July 16, 2010 | Posted by admin Question by fz: coaxial cable?????????????
why a coaxial cable might be preferable to household wiring or a lamp cord which consists of two side-by-side wires carrying currents in opposite directions?
Best answer:
Answer by Mr. Un-couth
The coaxial cable can conduct currents at much higher frequencies than the lamp cord or the household wiring. The frequency bandpass of a coaxial cable is much wider than that of household wiring or lamp cords.. The coaxial cable also shields the desired signal from outside interference from undesired signals that may be present in the area.
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Categories: Coaxial Cable | 
Tags: Cable, Coaxial | 
2 Comments »
1. Coaxial cable has a lower “characteristic impedance” than parallel wires. Most common ones are 50 ohm and 75 ohm, but not exclusively.
2. The internal conductor is shielded by the outer. The outer is grounded. Coax can be run on metalwork, even underground if desired.
3. Coax is considered an “unbalanced” feeder as in (2).
One has to assume you are talking of RF, not power or something.
Radio transmitters generally are matched to 50 ohm impedance. Coax is the preferred connecting medium (up to microwave frequencies). Antennas are also arranged to match to 50 ohms.
Twin parallel conductors can also be used, if the characteristic impedance is matched at both ends. Even a lamp cord. These are classified “open wire” feeders. They must be run clear of metalwork etc., and of course cannot be underground.
A coaxial cable may be usable for wiring a lamp cord, but, I won’t recommend for its use. Aside from its high cost,the ground shield may puncture the inner wire and result to short-circuit.Its voltage rating may be below 250 volts as compared with the royal cord wire.