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The best-known and simplest example of Ampère's force law, which underlaid (before 20 May 2019 [1]) the definition of the ampere, the SI unit of electric current, states that the magnetic force per unit length between two straight parallel conductors is
An optimization rule called Kelvin's Law (named for Lord Kelvin) states that the optimum size of conductor for a line is found when the cost of the energy wasted in the conductor is equal to the annual interest paid on that portion of the line construction cost due to the size of the conductors. The optimization problem is made more complex by ...
The phase velocity at which electrical signals travel along a transmission line or other cable depends on the construction of the line. Therefore, the wavelength corresponding to a given frequency varies in different types of lines, thus at a given frequency different conductors of the same physical length can have different electrical lengths.
Ladder line is an older, simpler form of parallel-wire line, often called open wire line. The configuration looks like a rope ladder , hence the name. It can either be purchased already made by a cable company, or home-made ; the construction is easy, though tedious, and originally all radio amateurs made their own open wire line.
In classical electromagnetism, Ampère's circuital law (not to be confused with Ampère's force law) [1] relates the circulation of a magnetic field around a closed loop to the electric current passing through the loop. James Clerk Maxwell derived it using hydrodynamics in his 1861 published paper "On Physical Lines of Force". [2]
By the Kelvin–Stokes theorem we can rewrite the line integrals of the fields around the closed boundary curve ∂Σ to an integral of the "circulation of the fields" (i.e. their curls) over a surface it bounds, i.e. = (), Hence the Ampère–Maxwell law, the modified version of Ampère's circuital law, in integral form can be rewritten as ((+)) =
A type of transmission line called a cage line, used for high power, low frequency applications. It functions similarly to a large coaxial cable. It functions similarly to a large coaxial cable. This example is the antenna feed line for a longwave radio transmitter in Poland , which operates at a frequency of 225 kHz and a power of 1200 kW.
Also called chordal or DC resistance This corresponds to the usual definition of resistance; the voltage divided by the current R s t a t i c = V I. {\displaystyle R_{\mathrm {static} }={V \over I}.} It is the slope of the line (chord) from the origin through the point on the curve. Static resistance determines the power dissipation in an electrical component. Points on the current–voltage ...