Question

A circuit containing a 80 mH inductor and a 60 µF capacitor in series is connected to 230 V, 50Hz supply. The resistance of the circuit is negligible. 

(a) Obtain the current amplitude and rms values. 

(b) Obtain the rms value of potential drops across each element, 

(c) What is the average transferred to the inductor? 

(d) What is the average power transferred to the capacitor? 

(e) What is the total average power absorbed by the circuit?

[‘average’ ‘implies’ averaged over one cycle;].

Answer 1

(a) For V = V₀ sin = ω_t

Where- sign appears if ωL > I/ ωC , and +sign appears if ωL < ωC.

I₀ = 11.6A, I_rms = 8.24A

(b) V_LCrms = 207V, V_Crms = 437 V

(c) Whatever be the current I in L, actual voltage leads current by π/2 . Therefore, average power consumed by L is zero. 

(d) For C, voltage lags by π/2 . Again average power consumed by C is zero. 

(e) Total average power absorbed is zero.