Power transferred to load

by Bromio
Tags: load, power, transferred
Bromio is offline
Sep7-11, 10:43 AM
P: 61
1. The problem statement, all variables and given/known data
Calculate the power transferred when Vi(t) = 50 cos (4π 10t) in the attached figure.

2. Relevant equations
P(load) = |V(load rms)||I(load rms)|cos(phase(V)-phase(I))

The solution must be P(load) = 3.82 W.

3. The attempt at a solution
I've calculated the Thevenin equivalent of the circuit outside the load. Vth = 27.1<12.5 and Zth = 12.1<75.96.

I've also calculated Zload = 50 Ω approximately.

V(load rms) is obtained by the voltage divisor. I got about 17.7<0 and I(load rms) = V(load rms)/Z(load) = 0.353<0.

So, using the formula in section 2., P(load) = 6.24 W, which is not the correct result.

Where have I made a mistake?

Thank you.
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