- #1
hogrampage
- 108
- 1
Homework Statement
Calculate the power absorbed by each element at t = 0-, t = 0+, and t = 200ms.
Homework Equations
P[itex]_{L}(t)[/itex] = [itex]\frac{V_{0}^{2}}{R}e^{-Rt/L}(1-e^{-Rt/L})[/itex]
P[itex]_{R}(t)[/itex] = [itex]\frac{V_{0}^{2}}{R}(1-e^{-Rt/L})[/itex]
P[itex]_{V}(t)[/itex] = -(P[itex]_{L}(t)[/itex] + P[itex]_{R}(t)[/itex])
The Attempt at a Solution
-10u(-t)V = -10V for t <= 0; 0V for t > 0
t = 0-: V = -10V, i = -10A
PR(0-) = (-10)2(1) = 100W
PL(0-) = 0W
PV(0-) = -100W
t = 0+: V = -10V, i = -10A
PR(0+) = (-10)2(1) = 100W
PL(0+) = 0W
PV(0+) = -100W
t = 200ms:
P[itex]_{L}(0.2)[/itex] = [itex]\frac{(-10)^{2}}{R}e^{-4(0.2)}(1-e^{-4(0.2)})[/itex] = 25W
P[itex]_{R}(0.2)[/itex] = [itex]\frac{(-10)^{2}}{R}(1-e^{-4(0.2)})[/itex] = 30W
P[itex]_{V}(0.2)[/itex] = -(25 + 30) = -55W
I'm not completely sure I did this problem correctly (particularly worried about the powers for 0- and 0+). If I did not, I would greatly appreciate any feedback (mistakes you see, hints, etc.). I don't want to go further in my homework until I understand this basic problem first.
Thanks!