To increase the resonant frequency in a series tuned circuit, what should you do?

In a series tuned circuit, the resonant frequency is determined by the inductance and capacitance of the circuit, and it can be calculated using the formula:

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

where ( f_r ) is the resonant frequency, ( L ) is the inductance, and ( C ) is the capacitance.

To increase the resonant frequency, you need to consider how the variables of inductance and capacitance affect the frequency. According to the formula, an increase in inductance ( L ) will result in a decrease in resonant frequency, while a decrease in capacitance ( C ) will lead to an increase in resonant frequency. This means decreasing the capacitance will effectively raise the resonant frequency.

Therefore, when the capacitance is reduced, the denominator in the square root decreases, leading to a higher resonant frequency. This is why decreasing the capacitance is the correct choice for increasing the resonant frequency in a series tuned circuit.