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LC oscillations
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Charge in an LC circuit oscillates like a mass on a spring.
ω = 1/√(LC)In an LC circuit charge oscillates at ω = 1/√(LC), swapping energy between the capacitor's electric field and the inductor's magnetic field.
L = 1 mH, C = 1 μF: f ≈ 5 kHz.
Resistance damps it.
In more detail
An LC circuit has an inductor and capacitor that exchange energy, oscillating at ω = 1/sqrt(LC). Electrical energy swaps between the capacitor's electric field and the inductor's magnetic field.
Real-world uses
- LC circuits set the frequency in radio transmitters and receivers.
- Oscillators in electronics use LC tanks to generate signals.
- Radio receivers use an LC circuit whose resonant frequency is tuned to pick out one station.
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Frequently asked questions
What is the frequency?
ω equals 1 divided by the square root of LC.
What is the analogy?
The capacitor plays the role of a spring and the inductor the role of mass.
Does an LC circuit oscillate forever?
Not in practice. Resistance in the circuit damps the oscillation, but a low-resistance circuit oscillates for many cycles.
Related topics in Oscillations & SHM
Resonance · Resonance examples · Amplitude vs frequency curve · Analogy between mechanical and electrical oscillators · Coupled oscillators · Normal modes