The LC circuit consists of L and C, L is the inductance coil and C is the capacitance. When these two elements form a closed loop, an oscillator is formed. The frequency of the oscillator is determined by the size of inductance and capacitance. The formula of capacitance is "Farah" and the formula of inductance is "Heng". If the oscillation circuit needs a frequency of 50 Hz, this formula is used to configure the capacitance and inductance. Then a capacitor is connected to the outside of the line, through which oscillation can be realized.

Maybe you have to ask, how can it generate a signal without power? Answer: Because you are connected to the power supply circuit, there may be only a little electrical signal to form an oscillation signal.

The oscillation signal with fixed frequency is very weak and needs to be amplified before it can be used.