Inductor

An inductor, also called a coil, choke, or reactor, is a <a href="/facts/Passivity_(engineering)/7oDeoqd3">passive</a> two-terminal <a href="/facts/Electronic_component/F3NBVv4Q">electrical component</a> that stores energy in a <a href="/facts/Magnetic_field/Ta8Ev588">magnetic field</a> when an <a href="/facts/Electric_current/Dc1xdnUX">electric current</a> flows through it. An inductor typically consists of an insulated wire wound into a <a href="/facts/Electromagnetic_coil/fk2ElSDk">coil</a>.
When the current flowing through the coil changes, the time-varying magnetic field induces an <a href="/facts/Electromotive_force/s6sNaHQL">electromotive force</a> (emf) (<a href="/facts/Voltage/EN2po6N2">voltage</a>) in the conductor, described by <a href="/facts/Faraday%2527s_law_of_induction/PFBreB0F">Faraday's law of induction</a>. According to <a href="/facts/Lenz%2527s_law/8Atydpcb">Lenz's law</a>, the induced voltage has a polarity (direction) which opposes the change in current that created it. As a result, inductors oppose any changes in current through them.
An inductor is characterized by its <a href="/facts/Inductance/oIxj7JxX">inductance</a>, which is the ratio of the voltage to the rate of change of current. In the <a href="/facts/International_System_of_Units/S7YLglNz">International System of Units</a> (SI), the unit of inductance is the <a href="/facts/Henry_(unit)/uwVv9zue">henry</a> (H) named for 19th century American scientist <a href="/facts/Joseph_Henry/Hr7CTgct">Joseph Henry</a>. In the measurement of magnetic circuits, it is equivalent to ⁠<a href="/facts/Weber_(unit)/Jvnyx1hA">weber</a>/<a href="/facts/Ampere/MScqkCgz">ampere</a>⁠. Inductors have values that typically range from 1 μH (10−6 H) to 20 H. Many inductors have a <a href="/facts/Magnetic_core/yojywmuo">magnetic core</a> made of iron or <a href="/facts/Ferrite_(magnet)/kBTM7Dqk">ferrite</a> inside the coil, which serves to increase the magnetic field and thus the inductance. Along with <a href="/facts/Capacitor/hyowqv7n">capacitors</a> and <a href="/facts/Resistor/JrsGReM6">resistors</a>, inductors are one of the three passive <a href="/facts/Linear_circuit/eDxQYWo2">linear</a> <a href="/facts/Circuit_element/CenJ4IkU">circuit elements</a> that make up electronic circuits. Inductors are widely used in <a href="/facts/Alternating_current/qxICS3xa">alternating current</a> (AC) electronic equipment, particularly in <a href="/facts/Radio/XFr909M2">radio</a> equipment. They are used to block AC while allowing DC to pass; inductors designed for this purpose are called <a href="/facts/Choke_(electronics)/NPh2C02U">chokes</a>. They are also used in <a href="/facts/Electronic_filter/ny7k6VxV">electronic filters</a> to separate signals of different <a href="/facts/Frequency/QUSbPaW8">frequencies</a>, and in combination with capacitors to make <a href="/facts/Tuned_circuit/tzEfI7Hf">tuned circuits</a>, used to tune radio and TV receivers.
The term inductor seems to come from <a href="/facts/Heinrich_Daniel_Ruhmkorff/3XHwg591">Heinrich Daniel Ruhmkorff</a>, who called the <a href="/facts/Induction_coil/vyAFgQsU">induction coil</a> he invented in 1851 an inductorium.

Inductor open-in-new

Inductor