Grade 11 physics
Electromagnetic Oscillations: the LC Circuit and Self-Oscillations
An LC circuit exchanges electric energy of a capacitor and magnetic energy of an inductor; losses damp the motion unless an active source restores energy.
1. Core ideas and learning goals
- In an ideal LC circuit, capacitor electric energy and inductor magnetic energy exchange while total energy is conserved.
- The natural angular frequency is omega0 = 1/sqrt(LC), so larger L or C lowers the frequency.
- Resistance converts electromagnetic energy to internal energy and damps free oscillations.
- Self-oscillation requires an active element and feedback that returns energy with the correct phase.
- A driven circuit shows resonance near its natural frequency, with amplitude limited by losses and nonlinearity.
2. Physical model
An LC circuit exchanges electric energy of a capacitor and magnetic energy of an inductor; losses damp the motion unless an active source restores energy.
An LC circuit exchanges electric energy of a capacitor and magnetic energy of an inductor; losses damp the motion unless an active source restores energy. The model links observable changes with measurable physical quantities and conservation laws.
Before applying a relation, specify the reference frame, system boundary, initial state and approximations. The conclusion is valid only while those conditions are satisfied.