When the resistance is greater than the capacitive reactance in a series RC circuit, what is the value of the phase angle?

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Answer 1 · 2015-06-22T22:27:46

The resistance (#R#), reactance (#X_C#), and overall impedance (#Z#) are related by:

#Z = sqrt(R^2 + X_C^2)#

Thus, there is a right triangle such that #Z# is the hypotenuse, and #R# and #X_C# are two legs. Using the angle between #Z# and #R#, we have:

#tanphi = (X_C)/R#

thus the phase shift #phi# is:

#phi = arctan((X_C)/R)#

Let's say that #R > X_C#. That means the argument of #arctan# is less than #1#, so #-pi/4 < phi < pi/4#.