HW set E

EE 201
Homework set E
Due: Oct. 3, 2014. Name_________________________ Sec _____________
22. For the circuit below, use the mesh-current method calculate the power being dissipated in
each resistor. R2
R3
35 !
50 !
IS1
VS +
I
R1
R
S2
4
–
1.5 A
20 !
40 !
25 V
0.75 A PR1 = ____________________________ PR2 = ____________________________ PR3 = ____________________________ PR4 = ____________________________ +
–
23. Use the mesh-current method to find the currents in R1, R4 , and R5 in the circuit below. R4 7 k!
iR4
iR1 = ____________________________
VS2
R2
3 k!
R3
2 k!
R1
5 k!
iR1
VS1 +
–
20 V
10 V
iR4 = ____________________________
R5
3 k!
iR5
iR5 = ____________________________
24. Use the mesh current method to find the voltages across each of the resistors in the circuit
below. (Note: You may need to employ an auxiliary equation or use supermesh methods to
solve this one.) IS2 2 mA
R1 5 k!
R3 2 k!
+ vR1 –
– vR3 +
+ V
IS1
5 mA
VS1 +
S2
–
–
25
V
15
V
+ vR4 –
– vR2 +
R2 1 k!
R4 7 k!
vR1 = ___________________________ vR2 = ____________________________ vR3 = ____________________________ vR4 = ____________________________ 25. We would like to design the circuit below so that 24 mW of power is dissipated in R5, and 48
mW of power is dissipated in R6. Determine the values of IS1 and IS2 needed in order for that
to happen. (Hint: Write the mesh equations and use what you know to work backwards.) IS1
IS1 = ________________________
VS +
–
12 V
R1 2 k!
R4 1.5 k!
R2
10 k!
R5
8 k!
IS2
IS2 = ________________________
R3 6 k!
R6 3 k!
26. Use the method of superposition to find the current through R3 in the circuit below. Pay
attention voltage polarities and current directions in each partial circuit. R4
VS1 +
IS
R2
– 1 k!
4 k!
40 V
4 mA
iR3 = ____________________________
V
R1
R3
iR3
S2
2 k!
3 k!
32 V
+
–
27. Use the method of superposition to find the power dissipated in R3 in the circuit below. (Be
careful: Look at the cautionary notes about calculating power when using superposition.) R1
R2
10 !
8!
VS1 +
VS2 R3
–
120 V
40 !
42 V
R4 14 !
R5 2 !
IS 8 A
PR3 = ____________________________
+
–
28. For the circuit below, use superposition to determine the value of IS such that there is no
power being dissipated in resistor R2. (Hint: Use superposition to determine how VS1 and VS2
affect R2. Then use superposition to determine the value of IS that will exactly cancel the
effects of VS1 and VS2.) IS
R1
R3
R5
2 k!
1 k!
4 k!
VS1 +
+ VS2 R2
R4
– 15 V 25 V –
10 k!
5 k!
IS = ____________________________

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