OF UNIVERSITY CALIFORNIA AT BERKELEY
EECS Department
EECS 40/42/100, Spring 2007 Prof. Chang-Hasnain Homework #4
Due at 6 pm in 240 Cory on Wednesday, 2/14/07 Total Points: 100 Put (1) your name and (2) discussion section number on your homework. You need to put down all the derivation steps to obtain full credits of the problems. Numerical answers alone will at best receive low percentage partial credits. No late submission will be accepted expect those with prior approval from Prof. Chang-Hasnain. 1. 2. 3. 4. 5. 6. 7. 8. 9. Hambley, P3.25 Hambley, P3.43 Hambley, P4.7 Hambley, P4.8 Hambley, P4.9 Hambley, P4.14 Hambley, P4.26 Hambley, P3.26. Do not assume constant current as stated in the problem. Consider the following circuit:
Assume the switch has been open for a very long time before closing at time t=0. We want to derive an expression for V1(t) for t>0. (a) Re-draw an equivalent series RC circuit (using Thevenin and combining the capacitors in series) (b) Solve for V1+V2 in your simplified circuit. Use (c) your result from problem 1 to obtain an expression for V1(t).
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UNIVERSITY OF CALIFORNIA AT BERKELEY
EECS Department
10. Consider the following circuit:
Assume switch a has been open, and b closed for a very long time. Then at time t=0, switch a closes and b opens. We will solve for the inductor current iL (going from top to bottom) in two ways: (a) Norton equivalent: i. Draw a Norton equivalent for the circuit before time t=0 and find the value of iL(0-). ii. Draw a Norton equivalent for the circuit after time t=0 and use this to solve for iL(t) for t>0. (Notice that we could not just draw one Norton equivalent for all times, because we can't include the switches.) (b) Superposition: i. Zero the current source and solve for the part of iL(t) due to the voltage source. ii. Zero the voltage source and solve for the part of of iL(t) due to the current source. iii. Add these together to get the total current. iv. Do your results agree with part (a)? Why or why not?
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