Question

In an L-R series circuit, a sinusoidal voltage V = V₀ sin ωt is applied. It is given that L = 35 mH, R = 11 Ω, V_rms = 220V, ω/2π = 50Hz and π = 22/7.  Find the amplitude of current in the steady state and obtain the phase difference between the current and the voltage. Also plot the variation of current for one cycle on the given graph.

Answer 1

Inductive reactance X_L = ωL

In L-R circuit voltage leads the current. Hence, instantaneous current in the circuit is, 

i = (20 A) sin (wt – π/4)

Corresponding i-t graph is shown in figure.