There are fully charged capacitors.

What happens if the capacitor draws current into the inductor?

What is the similarity between physical vibration and electrical vibration?

## LC oscillator

An LC circuit(also called a resonant circuit) is an electric circuit consisting of an inductor and a capacitor.

The circuit can act as an electrical resonator, an electrical analog of a tuning fork, storing energy oscillating at the circuit's resonant frequency.

## Find resonant frequency of LC oscillator

The resonant frequency of the LC vibration circuit is determined when the capacitor's reactance and the reactance of the inductor are the same.

\[ X_L = X_C \]

\[ 2 \pi fL = \frac{1}{2 \pi fC} \]

f: frequency (Hz)

L: Inductance of a Inductor(H)

C: Capacitance of a capacitor (F)

Resonant frequency is

\[ f = \frac{1}{2 \pi \sqrt{LC}} \]

The method of selecting the current of the desired frequency using the LC circuit is widely used in radio and wireless communication circuits.