An inductor is device that stores energy in the form of a magnetic field, and then uses this energy to induce current either in the same device. It is a type of coil.

How to determine Voltage induced

e = -L × (rate of change of current)

inductance (L),( -) sign indicates the polarity of voltage

Energy Stored in an inductor

The energy stored in an inductor is proportional to the product of the inductance and the square of the current flowing in it.

W = ½ L I *I 

where W is the energy (in Joules), L is the capacitance (in Henries), and I is the current flowing in the inductor (in Amps). 

Inductances add in series.

Inductances diminish in parallel.

Variable Inductors:

www.orenelliottproducts.com/variable.htm

Inductance of an inductor is computed as:

L= μ0. μr. n .n .A/l

where L is the inductance (in Henries), μ0 is the permeability of free space, μr is the relative permeability of the magnetic core, l is the mean length of the core (in meters), and A is the cross sectional area of the core (in square meters).

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