Energy in an Inductor

When a electric current is flowing in an inductor, there is energy stored in the magnetic field. Considering a pure inductor L, the instantaneous power which must be supplied to initiate the current in the inductor is

so the energy input to build to a final current i is given by the integral

Using the example of a solenoid, an expression for the energy density can be obtained.

Index

Inductance concepts

Capacitance concepts
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Energy in Magnetic Field

Solenoid Field
Solenoid Inductance

From analysis of the energy stored in an inductor,

the energy density (energy/volume) is

so the energy density stored in the magnetic field is

Index

Inductance concepts

Capacitance concepts
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