An LC circuit is much like an object oscillating back and forth on a spring. In theory no energy is lost, but in practice that's impossible. In the real world, harmonic oscillators lose energy due to friction and/or air resistance, and the oscillations in a circuit die out because of resistance in the circuit.
| Item | Harmonic Motion Variable | RLC Equivalent |
|---|---|---|
| Position, x | Charge, Q | |
| Velocity, v | Current, I | |
| Acceleration, a | dI/dt | |
| Inertia | Mass, m | Inductance, L |
| Starts the oscillations | Force, F | Potential Difference, DV |
| Provides restoring force | Spring constant, k | Inverse Capacitance, 1/C |
| Associated with energy loss | Damping parameter, b | Resistance, R |
| Energy associated with position | U = kx2/2 | U = Q2/2C |
| Energy associated with motion | U = mv2/2 | U = LI2/2 |