Electric Circuits, Fall 2015
Homework #3
Due: Oct. 27, 2015 (Tue., in class)
RULES:
 Please try to work on your own. Discussion is permissible, but identical submissions are
unacceptable!
 Please show all intermediate steps: a correct solution without an explanation will get zero
credit.
 Please submit on time. NO late submission will be accepted.
 Please prepare your submission in English only. No Chinese submission will be accepted.
3.1 [4%]
(a) In the circuit of Fig 1, calculate 𝑣0 and 𝑖0 when 𝑣0 = 1V.
(b) Find 𝑣0 and 𝑖0 when 𝑣𝑠 = 10V.
(c) What are 𝑣0 and 𝑖0 when each of the 1Ω resistors is replaced by a 10Ω resistor and 𝑣𝑠 = 10V.
Fig 1
3.2 [2%] Use linearity and assumption that V0  1V to find the actual value of V0 in Fig.2
Fig 2
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Electric Circuits, Fall 2015
Homework #3
Due: Oct. 27, 2015 (Tue., in class)
3.3 [5%] Using superposition, find Vo in the circuit of Fig.3.
Fig 3
3.4 [7%] Determine 𝑣𝑜 in the circuit of Fig 4 using the superposition principle.
Fig 4
3.5 [5%] Use superposition to find 𝑉𝑜 in the circuit of Fig 5.
Fig 5
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Electric Circuits, Fall 2015
Homework #3
Due: Oct. 27, 2015 (Tue., in class)
3.6 [3%] For the circuit in Fig 6, use source transformation to find 𝑖.
[Note: For problems 3.6-3.9, you should try your best to do all the source transformations: You
will not get full marks if you don’t do all the necessary transformations.]
.
Fig 6
3.7 [3%] Use source transformation to find the voltage 𝑉𝑥 in the circuit of Fig. 7.
Fig 7
3.8 [5%] Apply source transformation to find 𝑣𝑥 in the circuit of Fig. 8.
Fig 8
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Electric Circuits, Fall 2015
Homework #3
Due: Oct. 27, 2015 (Tue., in class)
3.9 [3%] Determine 𝑣𝑥 in the circuit of Fig.9 using source transformation.
Fig 9
3.10 [4%] Solve for the current i in the circuit of Fig.10 using Thevenin’s theorem.
Fig 10
3.11 [5%] Apply Thevenin’s theorem to find 𝑉𝑜 in the circuit of Fig. 11
Fig 11
3.12 [4%] Find the Thevenin equivalent at terminals a − b of the circuit in Fig. 12.
Fig 12
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Electric Circuits, Fall 2015
Homework #3
Due: Oct. 27, 2015 (Tue., in class)
3.13 [4%] For the circuit in Fig.13, obtain the Thevenin equivalent as seen from terminals:
1) a-b
2) b-c
Fig 13
3.14 [5%] Obtain the Norton equivalent at terminals of the circuit in Fig. 14.
Fig.14
3.15 [6%] Obtain the Thevenin and Norton equivalent circuits at terminals a-b for the circuit in Fig.15
Fig 15
3.16 [4%] Find the Thevenin equivalent of the circuit in Fig. 16
Fig 16
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Electric Circuits, Fall 2015
Homework #3
Due: Oct. 27, 2015 (Tue., in class)
3.17 [3%] Find the Norton equivalent for the circuit in Fig. 17.
Fig 17
3.18 [3%] Obtain the Thevenin equivalent seen at terminals of the circuit in Fig. 18.
Fig 18
3.19 [4%] The variable resistor R in Fig.19 is adjusted until it absorbs the maximum power from the
circuit.
(a) Calculate the value of R for maximum power.
(b) Determine the maximum power absorbed by R
Fig 19
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Electric Circuits, Fall 2015
Homework #3
Due: Oct. 27, 2015 (Tue., in class)
3.20 [6%] Compute the value of R that results in maximum power transfer to the 10- resistor in Fig 20.
Fig 20
3.21 [3%] For the circuit in Fig. 21, determine the value of Rsuch that the maximum power delivered
to the load is 3 mW.
Fig 21
3.22 [4%] A black box with a circuit in it is connected to a variable resistor. An ideal ammeter (with
zero resistance) and an ideal voltmeter (with infinite resistance) are used to measure current and
voltage as shown in Fig. 22. The results are shown in the Table 1.
(a) Find i when R=4 ohm.
(b) Determine the maximum power from the box.
Fig 22
Table 1
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Electric Circuits, Fall 2015
Homework #3
Due: Oct. 27, 2015 (Tue., in class)
3.23 [4%] A resistance array is connected to a load resistor R and a 9-V battery as shown in Fig. 23
(a) Find the value of R such that 𝑉0 = 1.8 𝑉
(b) Calculate the value of R that will draw the maximum current. What is the maximum current?
Fig 23
3.24 [4%] A common-emitter amplifier circuit is shown in Fig.24. Obtain the Thevenin equivalent to
the left of points B and E.
Fig 24
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