Oscillations in an LC Circuit

Consider an LC circuit like this:

This is a idealized situation -- there is no resistance. This is very similar to a mass-and-spring simple harmonic oscillator with no fricition.

The charge and the current in an LC circuit oscillate -- very much like a spring and mass simple harmonic oscillator.

For the spring-and-mass simple harmonic oscillator, we talked a lot about the energy changing from PE to KE and back and forth. For an LC circuit, the energy changes from being stored in the electric field between the plates of the capacitor to being stored in the magnetic field of the inductor.

The "natural frequency" or the "resonant frequency" of an LC circuit is

Remember, this is the angular frequency and is measured in radians per second and isrelated to the [ordinary] frequency which is measured in Hz or sec - 1 or [cycles] per second by


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(c) Doug Davis, 2002; all rights reserved