Ordinary Weston-type meter movements can measure only milliamperes at most, because the springs and practical coils can carry only limited currents.

High speed beams of cathode rays can also be steered and manipulated by electric fields created by additional metal plates in the tube to which voltage is applied, or magnetic fields created by coils of wire ( electromagnets ).

Traditionally, liquid helium is used to cool the coils because it has a boiling point of around 4 K at ambient pressure, and cheap metallic superconductors can be used for the coil wiring.

A side effect that can occur in air core coils in which the winding is not rigidly supported on a form is ' microphony ': mechanical vibration of the windings can cause variations in the inductance.

During this relaxation, a radio frequency signal ( electromagnetic radiation in the RF range ) is generated, which can be measured with receiver coils.

Experiments have demonstrated that currents in superconducting coils can persist for years without any measurable degradation.

It can also have the continuous coils replaced by a number of discrete coils producing a similar field.

TF coils can also be used to control the magnetic surface characteristics.

They're also used for resonant transformers such as Tesla coils where they can achieve reasonably low loss in spite of the high leakage inductance.

Although usually circular in cross-section, wire can be made in square or flattened rectangular cross-section, either for decorative purposes, or for technical purposes such as high-efficiency voice coils in loudspeakers.

However, energy can be stored inductively in superconducting coils.

A 1 km long mass driver made of superconducting coils can accelerate a 20 kg vehicle to 10. 5 km / s at a conversion efficiency of 80 %, and average acceleration of 5, 600 g.

appropriately designed helical coils can stabilize ideal kink modes at high beta, and lower-beta tests

This field strength can be calculated from the current as measured by the ammeter, the number of turns of the coil, and the radius of the coils.

Because of this, phone companies endeavor to remove load coils on copper loops that can operate without them, and conditioning lines to avoid them through the use of fiber to the neighborhood or node ( FTTN ).

The coupling between two wires can be increased by winding them into coils and placing them close together on a common axis, so the magnetic field of one coil passes through the other coil.

The cut-off phenomena of loading coils, an undesirable side-effect, can be exploited to produce a desirable filter frequency response.

Loading coils can still be found in some telephone landlines today but new installations would use more modern technology.

The " side circuits " within phantom circuits can be coupled to their respective voltage drops by center-tapped transformers, usually called " repeating coils ".

Instead, two circuits in a phantom configuration can be used to greatly reduce the inductance being inserted by the loading coils, and hence the loading effect.

A direct reading power factor meter can be made with a moving coil meter of the electrodynamic type, carrying two perpendicular coils on the moving part of the instrument.

Circular, H-shaped, double cone coils and other experimental variations can induce excitation or inhibition of neurons deeper in the brain including activation of motor neurons for the cerebellum, legs and pelvic floor.

All pickups use magnets to produce a magnetic field around the strings, and induce an electrical current in the coils as the strings vibrate.

As a Halbach magnet array passes over the loops of wire, the sinusoidal variations in the field induce a voltage in the track coils.

The mirror is aluminized by placing it in a vacuum chamber with electrically heated tungsten or nichrome coils that can evaporate aluminum.

A canned food manufacturer's materials inventory includes the ingredients to form the foods to be canned, empty cans and their lids ( or coils of steel or aluminum for constructing those components ), labels, and anything else ( solder, glue, etc.

Some designs have non-ferromagnetic projectiles, of such as aluminum or copper, with the armature of the projectile acting as an electromagnet with internal current induced by pulses of the acceleration coils.

In this early configuration by Bedford, Peer, and Tonks from 1939, an aluminum plate is placed on two concentric cylindrical coils, and driven with an AC current.

The General Motors Rotary Combustion Engine ( GMRCE ) had two rotors displacing, twin distributors and coils, and aluminum housing,

* In the 1960s, motors returned to the company's product line with an award winning new model featuring an extruded aluminum frame and automatically wound stator coils.

Their transformers featured aluminum primary winding and were cast using relatively inexpensive molds, allowing them to produce cast coil transformers in a variety of KVA capacities, primary and secondary voltages and physical coil sizes, including low profile coils for mining and other specialty applications.

In modern aluminum silvering, a sheet of glass is placed in a vacuum chamber with electrically heated nichrome coils that can sublime aluminum.

A coil tap is a wiring feature found on some electrical transformers, inductors and coil pickups, all of which are sets of wire coils.

Multilayer coils have the problem of interlayer capacitance, so when multiple layers are needed the shape needs to be radically changed to a short coil with many layers so that the voltage between consecutive layers is smaller ( making them more spiral like ).

These contain magnets that are tightly wrapped in a coil, or coils, of copper wire.

This was followed by Benz, Mors, Turcat-Mery, and Nesseldorf, and soon was used on most cars up until about 1918 in both low voltage ( voltage for secondary coils to fire the spark plugs ) and high voltage magnetos ( to fire the spark plug directly, similar to coil ignitions, introduced by Bosch in 1903 ).

This is achieved with a solenoid operating a ratchet and cam mechanism, or by having two opposing coils with an over-center spring or permanent magnet to hold the armature and contacts in position while the coil is relaxed, or with a remanent core.

; Heliotron: A stellarator configuration in which a helical coil is used to confine the plasma, together with a pair of PF coils to provide a vertical field.

The original Heliac consists only of circular coils, and the flexible heliac ( H-1NF, TJ-II, TU-Heliac ) adds a small helical coil to allow the twist to be varied by a factor of up to 2.

The maximum acceleration part spaces the coils at constant distances, and synchronize the coil currents to the bucket.

The galvanometer is first aligned so that the coil is parallel to the geomagnetic field, whose direction is indicated by the compass when there is no current through the coils.

A DSL signal cannot pass through a properly installed and working load coil, while voice service cannot be maintained past a certain distance without such coils.

American early and middle 20th century telephone cables had load coils at intervals of a mile ( 1. 61 km ), usually in coil cases holding many.

The coils must be removed to pass high frequencies, but the coil cases provided convenient places for repeaters for digital T-carrier systems, which could carry 1. 5 Mbit / s across that distance.

A second stationary field coil, perpendicular to the voltage coils, carries a current proportional to current in one phase of the circuit.

Magnetostrictive speaker drivers have some special advantages: they can provide greater force ( with smaller excursions ) than other technologies ; low excursion can avoid distortions from large excursion as in other designs ; the magnetizing coil is stationary and therefore more easily cooled ; they are robust because delicate suspensions and voice coils are not required.

In 1931, he demonstrated that a magnetic coil could act as an electron lens, and used several coils in a series to build the first electron microscope in 1933.

These coils have high power losses due to ohmic heating of the coil wire, making the antenna inefficient.

Rollin White developed a form of water tube steam generator which consisted of a series of stacked coils with two novel features: the first, and most fundamental, was that the coils were all joined at the top of the unit, which allowed water to flow through only when pumped, allowing control of the steam generation ; the second was pulling steam from the lowest coil, closest to the fire, which allowed for the control of steam temperature.