In a series RLC circuit, capacitance is ____ proportional to frequency.
A) directly
B) inversely

Question

Quizplus · Accepted Answer

In a series RLC circuit, the impedance is a function of frequency and is given by Z = R + j(XL - XC), where XL and XC are the reactances of the inductor and capacitor, respectively. At resonance, XL = XC, so the impedance is purely resistive and has its minimum value. At frequencies above resonance, XC > XL, so the impedance is dominated by the capacitive reactance and increases with frequency. In contrast, at frequencies below resonance, XL > XC, so the impedance is dominated by the inductive reactance and also increases with frequency. Thus, capacitance is inversely proportional to frequency since higher capacitance values result in lower capacitive reactances and therefore lower impedances at higher frequencies.

In a Series RLC Circuit, Capacitance Is ____ Proportional to Frequency