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Resonant tank (LC)

Transients · Advanced · about 20 minutes · part of Zen’s Electronics Design Mastery

Charge a capacitor, then hand it to an inductor. Energy sloshes back and forth between the electric and magnetic fields at f₀ = 1 / (2π√LC), dying away through the coil resistance.

Resonant tank (LC): the circuit on the simulator's bench

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How it works

f₀ = 1 / (2π√LC) = 50.33 Hz

With coil resistance r = 8 Ω: damped frequency fd = √(ω₀² − α²)/2π = 50.33 Hz, decay time 1/α = 2L/r = 250 ms

Q = ω₀L / r = 39.5, so it rings for roughly Q cycles.

Try it on the bench

  1. Click the changeover switch S to B and watch the decaying sine on the scope.
  2. Swap C for 2.2 µF. The frequency rises by √(10/2.2) ≈ 2.1×.

Parts on the bench

In the course

Zen’s Electronics Design Mastery, module “Capacitors, Inductors & Time”.

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