A loading coil or load coil is an inductor that is inserted into an electronic circuit to increase its inductance. The term originated in the 19th century for inductors used to prevent signal distortion in long-distance telegraph transmission cables. The term is also used for inductors in radio antennas, or between the antenna and its feedline, to make an electrically short antenna resonant at its operating frequency.
The concept of loading coils was discovered by Oliver Heaviside in studying the problem of slow signalling speed of the first transatlantic telegraph cable in the 1860s. He concluded additional inductance was required to prevent amplitude and time delay distortion of the transmitted signal. The mathematical condition for distortion-free transmission is known as the Heaviside condition. Previous telegraph lines were overland or shorter and hence had less delay, and the need for extra inductance was not as great. Submarine communications cables are particularly subject to the problem, but early 20th century installations using balanced pairs were often continuously loaded with iron wire or tape rather than discretely with loading coils, which avoided the sealing problem.
Loading coils are historically also known as Pupin coils after Mihajlo Pupin, especially when used for the Heaviside condition and the process of inserting them is sometimes called pupinization.
A loadingcoil or loadcoil is an inductor that is inserted into an electronic circuit to increase its inductance. The term originated in the 19th century...
Look up loading in Wiktionary, the free dictionary. Loading may refer to: Carbohydrate loading, a strategy employed by endurance athletes to maximize the...
called a "quarter-wave whip" (although often shortened by the use of a loadingcoil; see Electrically short whips below). For example, the common quarter-wave...
An electromagnetic coil is an electrical conductor such as a wire in the shape of a coil (spiral or helix). Electromagnetic coils are used in electrical...
cables supported several feet above the ground under the antenna. A large loadingcoil is required at the antenna feed point to cancel the capacitive reactance...
type of coil car, coils of sheet metals were carried on-end or in cradles in open or covered gondolas. Load shifting, damage, and awkward loading and unloading...
the inductance being inserted by the loadingcoils, and hence the loading effect. It works because the loadingcoils used on balanced lines have two windings...
important contributions were to the theory and implementation of the use of loadingcoils and the first wave filters designed to what was to become known as the...
disqualified from eligibility because of loadingcoil placement. Because of this, phone companies endeavor to remove loadingcoils on copper loops that can operate...
A Tesla coil is an electrical resonant transformer circuit designed by inventor Nikola Tesla in 1891. It is used to produce high-voltage, low-current,...
shorter antennas include loadingcoils to make the antenna impedance the same as a physically longer antenna. The loadingcoil may be on the bottom, middle...
circuit to another circuit, or multiple circuits. A varying current in any coil of the transformer produces a varying magnetic flux in the transformer's...
would compress 1 inch with 100 pounds (45 kg) of load. Types of coil spring are: Tension/extension coil springs, designed to resist stretching. They usually...
“electrical”) antennas, matching using a loadingcoil also generates high voltages at the antenna end(s) and in the loadingcoil, however unlike capacitors, the...
feedpoint impedance includes a large capacitive reactance requiring a loadingcoil or other matching network in order to be practical, especially as a transmitting...
magnetic material, characterized by high permeability and low coercivity. Loadingcoil Mu-metal Sendust Supermalloy (a material with even higher magnetic permeability)...
as inverted-L or T antennas, which are brought into resonance with a loadingcoil at their base. Receiving antennas do not have to be as efficient as transmitting...
/2} ) will have capacitive reactance. Adding an inductor (coil of wire), called a loadingcoil, at the feedpoint in series with the antenna, with inductive...
antenna (given by the graph below), and includes a reactance, usually a loadingcoil, to tune out the reactance of the antenna, to make it resonant at the...
A Rogowski coil, named after Walter Rogowski, is an electrical device for measuring alternating current (AC) or high-speed current pulses. It sometimes...
moving coils, A and B, are connected in parallel with the circuit load. One coil, A, will be connected through a resistor and the second coil, B, through...
resistance, which require a large loadingcoil and low-resistance counterpoise system. Loop antennas consist of a loop (or coil) of wire. Loop antennas interact...
Electrician, 3 June 1887 James E. Brittain, "The Introduction of the LoadingCoil: George A. Campbell and Michael I. Pupin", Technology and Culture, Vol...
inductors are known as loadcoils and reduce attenuation for voiceband frequencies but increase it on higher frequencies. Loadcoils reduce distortion in...
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