Question

Find the value of the phase lag/lead between the current and voltage in the given series LCR circuit. Without making any other change, find the value of the additional capacitor, such that when 'suitably joined' to the capacitor (C = 2μF) as shown. What would make the power factor of this circuit as unity ?

Answer 1

The current, I, leads the voltage, V, by an angle ϕ where

To make power factor as unity, we need to have X_C also equal to 100 Ω . For this C needs to have a value of 10μF.

We, therefore need to put an additional capacitor of (10-2), i.e. 8 μF in parallel with given capacitor.