The quality factor (Q) is a dimensionless parameter that quantifies how underdamped an oscillator is—that is, how long it oscillates before its energy significantly decreases.
What Q Represents:
- A high Q means the oscillator loses very little energy per cycle, so it oscillates for a long time with slow decay.
- A low Q indicates stronger damping, causing oscillations to die out quickly.
Physical Meaning:
- Q relates to the sharpness of the resonance peak: higher Q oscillators have narrow, well-defined resonances.
- It is proportional to the ratio of the stored energy to the energy lost per cycle.
Examples:
- A tuning fork has a high Q, producing a clear, sustained note.
- A car shock absorber is designed for low Q to quickly damp vibrations for comfort and safety.
Importance:
- Q helps in designing systems like clocks, radios, and lasers, where controlling damping and resonance is crucial.
- In mechanical, electrical, and optical oscillators, Q influences performance and stability.