Inductance and Electromagnetic Induction

Study Notes

Inductance is a property of an electrical conductor, which is measured by the size of the electromotive force (emf) or voltage induced in it, compared with the rate of change of the electric current that produces the voltage. It is a measure of the ability of a conductor to store energy for a given amount of current flow. Inductance is symbolically denoted with a capital "L" and is measured in the unit of the Henry, abbreviated as "H".

The principle of electromagnetic induction is exploited throughout electrical engineering in generators, transformers, solenoids, transducers, relays, and the inductor as a circuit element. The inductor is used in AC circuits from power line frequencies to RF to suppress electromagnetic limit in-rush currents, cancel capacitive reactance in impedance matching, form a tuned resonant circuit with capacitors, and more.

Inductance is the tendency of an electrical conductor to oppose a change in the electric current flowing through it. The electric current produces a magnetic field around the conductor, and the magnetic field strength depends on the magnitude of the electric current. From Faraday's law of induction, the electromotive force is proportional to the rate of change of the electric current.

In designing an inductor, the only variables that determine the value of the inductor are the number of turns, the physical size of the coil, and the relative permeability of the core material. The formula for approximating the inductance of a cylindrical coil is given by equation in the article.

An inductor resists sudden changes of current, and it tolerates gradual changes. When an inductor is connected to a switch, there is a paradox when the switch is thrown open. The inductor current cannot change instantaneously, and this can be tricky, since it is very easy to create a very big change of current if you open or close a switch. To protect sensitive components from high voltages generated by an inductor, it is important to be careful with the voltage and change of current[5

Description

Test your knowledge of inductance, electromagnetic induction, and the role of inductors in electrical engineering. Explore the principles of inductance, the formula for approximating the inductance of a cylindrical coil, and the behavior of inductors in circuits.