Abstract: The influence of inductor frequency characteristic on a RLC series resonant circuit is analyzed，and a method of roughly measuring the resonant frequency is introduced. The equations of the resonant curve half-peak bandwidths for the load resistor and LC component are derived，and the applying conditions of the equations are also discussed. Then，an inductor with high quantity factor is fabricated，and the experimental results are in agreement with the theoretical analysis. The results show that the higher the inductor’s Q is and the smaller the rL is，the narrower the resonant curve half-peak bandwidth is and the more accuracy the measurement is. In addition，the resonant curve of the load resistance is narrower than that of LC component when R is greater than 0.64 rL .

Key words: RLC circuit, resonance, frequency characteristic, quantity factor