Which of the following can be used to determine the Q of a series-tuned circuit?
The ratio of inductive reactance to capacitive reactance
The frequency shift
The bandwidth of the circuit's frequency response✓Correct answer
The resonant frequency of the circuit
Explanation
Q is the resonant frequency divided by the −3 dB bandwidth of the response, so measuring how wide the response curve is at resonance yields Q. The resonant frequency alone does not, and neither does a reactance ratio, since at resonance those reactances are equal regardless of the losses that set Q.