電路學(一) Homework 02 Deadline：11/04

姓名/Name: 學號/Student ID:

請同學將姓名與學號寫在作業上方(如上格式)，並請用空白 A4 寫(直向)，並依題
目順序作答，並清 楚寫出計算順序與答案。作業繳交時限為 11/04 週一上課前。
若有違反或使助教批改上難以辨認， 以助教批改成績為主。

Chapter 4, Problem 1.
Calculate the current io in the circuit of Fig. 4.69. What value of input voltage is
necessary to make io equal to 5 amps?

Figure 4.69

Chapter 4, Problem 5.
For the circuit in Fig. 4.73, assume vo = 1 V, and use linearity to find the actual value of
vo.

Figure 4.73

Chapter 4, Problem 17.

Use superposition to obtain vx in the circuit of Fig. 4.85.

Figure 4.85
Chapter 4, Problem 21
Using Fig. 4.89, design a problem to help other students better understand source
transformation.

Figure 4.89

Chapter 4, Problem 32.

Use source transformation to find ix in the circuit of Fig. 4.100.

Figure 4.100

Chapter 4, Problem 45.

Find the Thevenin equivalent of the circuit in Fig. 4.112 as seen by looking into terminals
a and b.

Figure 4.112
Chapter 4, Problem 50.
Obtain the Norton equivalent of the circuit in Fig. 4.116 to the left of terminals a-b. Use
the result to find current i

Figure 4.116

Chapter 4, Problem 62.

Find the Thevenin equivalent of the circuit in Fig. 4.128.

Figure 4.128

Chapter 4, Problem 78.

For the transistor model in Fig. 4.111, obtain the Thevenin equivalent at terminals a-b.

Figure 4.111
Chapter 4, Problem 93.

The circuit in Fig. 4.149 models a common-emitter transistor amplifier. Find ix

using source transformation.

Figure 4.149

Chapter 5, Problem 1.
Suppose your circuit laboratory has the following standard commercially
available The equivalent model of a certain op amp is shown
in Fig. 5.43. Determine:
(a) the input resistance.
(b) the output resistance.
(c) the voltage gain in dB.

Figure 5.43

Chapter 5, Problem 8.
Obtain vo for each of the op amp circuits in Fig. 5.47.

Figure 5.47
Chapter 5, Problem 16

Using Fig. 5.55, design a problem to help students better understand inverting op
amps.

Figure 5.55

* Chapter 5, Problem 18.

For the following circuit, solve for the Thevenin equivalent circuit looking into
terminals A and B.

Figure 5.57
Chapter 5, Problem 27.

Find vo in the op amp circuit in Fig. 5.65.

Figure 5.65

Chapter 5, Problem 30

In the circuit shown in Fig. 5.68, find ix and the power absorbed by the 20-k
resistor.

Figure 5.68

Chapter 5, Problem 36
For the circuit shown in Fig. 5.73, find the Thèvenin equivalent at terminals a-b.
(Hint: To find RTh, apply a current source io and calculate vo.)

Figure 5.73
Chapter 5, Problem 44

Show that the output voltage vo of the circuit in Fig. 5.78 is

vo =
(R3 + R4 ) (R v + R v )
R3 (R1 + R2 )
2 1 1 2

Figure 5.78

Chapter 5, Problem 48

The circuit in Fig. 5.80 is a differential amplifier driven by a bridge. Find vo.

Figure 5.80
Chapter 5, Problem 53

The ordinary difference amplifier for fixed-gain operation is shown in Fig. 5.81(a).
It is simple and reliable unless gain is made variable. One way of providing gain
adjustment without losing simplicity and accuracy is to use the circuit in Fig.
5.81(b). Another way is to use the circuit in Fig. 5.81(c). Show that:

(a) for the circuit in Fig. 5.81(a),

vo R2
=
vi R1

(b) for the circuit in Fig. 5.81(b),

vo R2 1
=
vi R1 1 + R1
2 RG

(c) for the circuit in Fig. 5.81(c),

vo R2  R 
= 1 + 2 
vi R1  2 RG 

Chapter 5, Problem 56.

Using Fig. 5.83, design a problem to help other students better understand
cascaded op amps.

Figure 5.83
For Prob. 3.75.
Chapter 5, Problem 67

Obtain the output vo in the circuit of Fig. 5.94.

Figure 5.94

Chapter 5, Problem 74

Find io in the op amp circuit of Fig. 5.100.

Figure 5.100
Chapter 5, Problem 77

Solve Prob. 5.48 using PSpice and op amp LM324.

5,48 The circuit in Fig. 5.78 is a differential amplifier driven by a bridge. Find vo.

Figure 5.78

Chapter 5, Problem 79

Determine vo in the op amp circuit of Fig. 5.102 using PSpice.

+
–

Figure 5.102
hapter 5, Problem 84

A four-bit R-2R ladder DAC is presented in Fig. 5.103.

(a) Show that the output voltage is given by

V V V V 
− Vo = R f  1 + 2 + 3 + 4 
 2 R 4 R 8R 16R 

(b) If Rf = 12 k and R = 10 k, find |Vo| for [V1V2V3V4] = [1011] and

[V1V2V3V4] =
[0101].

Figure 5.103

Chapter 5, Problem 90
The op amp circuit in Fig. 5.107 is a current amplifier. Find the current gain io/is
of the amplifier.

Figure 5.107
Chapter 5, Problem 93

A voltage-to-current converter is shown in Fig. 5.110, which means that iL = Avi if

R1R2 = R3R4. Find the constant term A.

Figure 5.110