# Xiang-HW1Practice - ECE 35 HW1 Practice Problems The...

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ECE 35 HW1 Practice Problems The following problems are from Dorf & Svoboda Intro. to Electric Circuits 9thedition. They not part of the homework and therefore will not be turned in. However, it is recommended that you do them since some of these problems will be similar to the test problems. (SPOILER ALERT: Solutions on the next page.) 1)P 1.7-2 2)DP 1-2 3)P 2.4-10 4)P 2.5-4 5)P 2.6-6 6)P 2.7-1 7)DP 2-2
Solutions P 1.7-2 Notice that the element voltage and current of some branches do not adhere to the passive convention. The sum of the powers absorbed by each branch are: -(3 V)(3 A)+(3 V)(2 A)+ (3 V)(2 A)+(4 V)(3 A)+(-3 V)(-3 A)+(4 V)(-3 A) = -9 W + 6 W + 6 W + 12 W + 9 W -12 W 0 W The element voltages and currents do not satisfy conservation of energy and cannot be correct. DP 1-2  888820 10.030.6 1Wttttp teeeeHere is a MATLAB program to plot p(t): clear t0=0; % initial time tf=1; % final time dt=0.02; % time increment t=t0:dt:tf; % time v=20*(1-exp(-8*t)); % device voltage i=.030*exp(-8*t);