For this given circuit bellow, how do I calculate the phase angle? For my example I have values, but I would like the general approach formula, this is what I have done so far

Calculated X_L = 2*pifL X_C = -1/(2*pifL)

X_CL = (X_L - X_C)

Z = R*jX_CL/(R+jX_CL)

However at this point (with values) I am getting the wrong answer. Where am I doing wrong?

PS. I inserted the values in Wolframalpha and got the wrong angle hence why I am here.



EDIT: I'll include values if it helps explaination f = 24 Hz L = 6 H c = 43 microF R = 176 U = 8V

  • \$\begingroup\$ The conversion is simple to do, so in anyway \$\endgroup\$ Apr 25, 2017 at 19:17

1 Answer 1


Xc=1/2pifC (you used L instead of C in your equation). Also, if you use a minus sign for Xc, then you must add Xl an Xc, not subtract them. You equations are correct if you remove the minus sign from Xc. The phase angle of the input impedance is: Θ = arctan(R/(Xl-Xc). Substituting your numbers, Xl=150.80, Xc=154.22, Θ=-88.89°.


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