A sinusoidal voltage Δv = (65 V) sin (140t) is applied to a series RLC circuit with L = 100 mH, C = 175 μF, and R = 42 Ω.

(a) What is the impedance of the circuit?

1 answer

R = 42 Ohms.
Xc = 1/W*C = 1/(140*175*10^-6)=40.8 Ohms
Xl = W*L = 140*100*10^-3 = 14 Ohms.

Z^2 = R^2 + (Xl-Xc)^2 = 2482.24
Z = 49.82 Ohms.

tanA = (Xl-Xc)/R = (14-40.8)/42=-0.63810
A = -32.54o = Phase angle.

Z = 49.82 Ohms @ -32.54o.