Consider a series LRC circuit with R=74 ohm, L=0.28 H and C=0.7 muF. The current
ID: 1291181 • Letter: C
Question
Consider a series LRC circuit with R=74 ohm, L=0.28 H and C=0.7 muF. The current is 17 mA amplitude at 0.7 kHz. Remember omega = 2pif, where f is the frequency in cycles per second or Hz. Find the angular resonant frequency of oscillations. Express the answer with one decimal place. A series ac circuit is shown. The inductor has a reactance of 128 ohm and an inductance of 106 mH. A 64 ohm resistor and a capacitor, whose reactance is 177 ohm, are also in the circuit. The rms current in the circuit is 2 A. In Figure, the phase angle (in degrees) of the circuit is:Explanation / Answer
resonant frequency W^2 = 1/LC
W^2 = 1/(0.28 * 0.7 e-6)
W^2 = 5.1*10^6
W = 2pif = 2258.75
f = 719.35 Hz
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phase angle tan theta = (Xl-Xc)/R
tan theta = (128-177) /64
tan theta = -0.765
theta = pahse angle = -37.43 deg