Inductor
An inductor is an electrical device used in electrical circuits because it acts like inertia in the electrical circuit. Just like inertia opposes the change in state of motion, inductor opposes the change in electric current.
An inductor is usually made from a coil of conducting material, like copper wire, that is then wrapped around a core made from either air or a magnetic metal. If you use a more magnetic material as the core, you can get the magnetic field around the inductor to be pushed in towards the inductor, giving it better inductance.[1] Small inductors can also be put onto integrated circuits using the same ways that are used to make transistors. Aluminum is usually used as the conducting material in this case.
How inductors work
While a capacitor reacts against changes in voltage, an inductor reacts against changes in current. The inductor affects the current like inertia.
In general, the relationship between the time-varying voltage v(t) across an inductor with inductance L and the time-varying current i(t) passing through it is described by the differential equation:
[math]\displaystyle{ v(t) = L \frac{di}{dt}. }[/math][2]
How inductors are used
Inductors are used often in analog circuits.[3] Two or more inductors that have coupled magnetic flux make a transformer. Transformers are used in every power grid around the world.
Inductors are also used in electrical transmission systems, where they are used to lower the amount of voltage an electrical device gives off or lower the fault current. Because inductors are heavier than other electrical components, people have been using them in electrical equipment less often.[3]
Inductors with an iron core are used for audio equipment, power conditioning, inverter systems, rapid transit and industrial power supplies.[4]
Electrical engineers like to reduce diagrams of electrical circuits, no matter how complicated, to an equivalent circuit consisting of a network of just four different types of component. These four basic components are emfs, resistors, capacitors, and inductors. An inductor is usually represented by a little solenoid in circuit diagrams. In practice, inductors generally consist of short air-cored solenoids wound from enameled copper wire.
Inductor Media
The circuit diagram for an inductor
An electric current I creates a magnetic field B around it
Schematic using current's exit terminal as reference for voltage
Example of signal filtering. In this configuration, the inductor blocks AC current, while allowing DC current to pass.
Example of signal filtering. In this configuration, the inductor decouples DC current, while allowing AC current to pass.
Collection of RF inductors, showing techniques to reduce losses. The three top left and the ferrite loopstick or rod antenna, bottom, have basket windings.
A variety of types of ferrite core inductors and transformers
Laminated iron core ballast inductor for a metal halide lamp
Toroidal inductor in the power supply of a wireless router
A "roller coil", an adjustable air-core RF inductor used in the tuned circuits of radio transmitters. One of the contacts to the coil is made by the small grooved wheel, which rides on the wire. Turning the shaft rotates the coil, moving the contact wheel up or down the coil, allowing more or fewer turns of the coil into the circuit, to change the inductance.
Related pages
References
- ↑ "Inductors 101" (PDF). Vishay Intertechnology, Inc. 2008-08-12. Retrieved 2010-10-02.
- ↑ "Inductors and Calculus", All About Circuits, Retrieved June 8, 2016
- ↑ 3.0 3.1 "Inductor Archived 2019-12-08 at the Wayback Machine", Engineersblogsite.com, Retrieved June 8, 2016
- ↑ "Highly Efficient Iron Core Inductors", Agile Magnetics, Retrieved June 8, 2016
Other websites
- How stuff works How inductors work, made very simple.