大学MOOC 模拟电子技术基础(西安邮电大学)1205808825 最新慕课完整章节测试答案

第十章中文测验

1、单选题：
​集成运放的输入级一般由▁▁▁▁组成。‏​‏
选项：
A: 差分放大电路
B: 电压放大电路
C: 功率放大电路
D: 偏置电路
答案: 【 差分放大电路】

2、单选题：
差分放大器的两个输入电压分别为Ui1=0.04V，Ui2=0.08V，则其共模输入电压为▁▁▁▁。‍‍‍
选项：
A: 0.04V
B: 0.06V
C: 0.08V
D: 0.12V
答案: 【 0.06V】

3、单选题：
差分放大器的两个输入电压分别为Ui1=0.08V，Ui2=0.04V，则其差模输入电压为▁▁▁▁。‎‎‎
选项：
A: 0.04V
B: 0.06V
C: 0.08V
D: 0.12V
答案: 【 0.04V】

4、单选题：
‎典型的差分放大电路由双端输出变为单端输出，共模电压放大倍数（   ）。‌‎‌
选项：
A: 变大
B: 变小
C: 不变
D: 无法确定
答案: 【 变大】

5、单选题：
共模抑制比是差分放大电路的一个主要技术指标，它是反映放大电路（  ）的能力。‏‎‏
选项：
A: 消除失真
B: 输入电阻高
C: 放大差模，抑制共模
D: 输出电阻低
答案: 【 放大差模，抑制共模】

第十章测验

1、单选题：

‏Under difference-mode operation, the difference-mode voltage gain for this circuit is _______.

‏

‏

‏选项：
A: 0.0397
B: 80
C: 40
D: 0.08
答案: 【 40】

2、单选题：
‍The operational amplifier will only slightly amplify signals __ ___.‍‍‍
选项：
A: when the supply voltages are more then ±25 V
B: when the supply voltages are less then ±5 V
C: that are common on both the inputs
D: that are different on both the inputs
答案: 【 that are common on both the inputs】

3、单选题：
‍ The inverting and noninverting inputs to an op-amp are used to drive a(n) _______ amplifier. ‍‍‍
选项：
A: inverting
B: noninverting
C: differential
D: open-loop
答案: 【 differential】

4、单选题：
‌When a given op-amp has a common-mode input of 10 V, the output of the device is 10 V. When the device has a differential input of 2 mV, the output of the device is 10 V. What is the CMPR of the device? ‌‌‌
选项：
A: 5 : 1
B: 5000 : 1
C: 1000 : 1
D: 5,000,000 : 1
答案: 【 5000 : 1】

5、单选题：
‍The bandwidth of an amplifier is _______.‎‍‎
选项：
A: the range of frequencies over which gain remains relatively constant
B: the range of frequencies between the lower and upper 3 dB frequencies
C: the range of frequencies found using f2 – f1
D: All of the above
答案: 【 All of the above】

6、单选题：

‌The main features of a difference pair, such as the circuit shown here, are _______.

​

‌

​选项：
A: very high input impedance and very high voltage gain
B: very high input impedance and moderate voltage gain
C: moderate input impedance and very high voltage gain
D: moderate input impedance and moderate voltage gain
答案: 【 very high input impedance and very high voltage gain】

7、单选题：

‎Under common-mode operation, the common-mode voltage gain for this circuit is _______.

‍

‎

‍选项：
A: 0.0397
B: 80
C: 40
D: 0.08
答案: 【 0.0397】

8、单选题：

‌Under single-ended operation the differential-mode voltage gain for this circuit is ___ ____.

‏

‌

‏选项：
A: 33.33
B: 66.66
C: 133.33
D: 266.66
答案: 【 66.66】

9、单选题：
​The common mode rejection ratio (CMRR) is the ratio of _______.‌​‌
选项：
A: the difference mode gain to the common mode gain
B: the common mode gain to the difference mode gain
C: noninverting gain to inverting gain
D: inverting gain to noninverting gain
答案: 【  the difference mode gain to the common mode gain】

10、单选题：

‍For this AC equivalent circuit of an op-amp, the input signal is applied between the input terminals and sees an input impedance Ri. This impedance _______.

‍

‍

‍选项：
A: is a few hundred ohms
B: is a few kilohms
C: is a few hundred kilohms
D: depends on the op-amp used. It could be a few hundred ohms to a few hundred kilohms
答案: 【 is a few hundred kilohms】

11、单选题：

‏Under common-mode operation, the common-mode voltage gain is _______.

​

‏

​选项：
A: 0.133
B: 33.33
C: 66.66
D: 0.266
答案: 【 0.133】

12、单选题：
‍Which of the following statements is true? ‍‍‍
选项：
A: Op-amps are high-gain dc amplifiers
B: Op-amps have extremely high input impedance.
C: Op-amps have extremely low output impedance.
D: All of the above
答案: 【  All of the above】

13、单选题：
‎In the integrated operational amplifier circuit, the coupling mode is adopted between the circuit of all levels.‍‎‍
选项：
A: direct
B: transformer
C: resistance capacitance
D: photoelectricity
答案: 【 direct】

14、单选题：
‎The input stage of an integrated operational amplifier is generally composed of .‌‎‌
选项：
A: differential amplifier circuit
B: voltage amplifier circui
C: power amplifier circuit
D: current source
答案: 【 differential amplifier circuit】

15、单选题：
‏The two input voltages of the differential amplifier are Ui1 = 0.04V ,and Ui2 = 0.08V, the common mode input voltage .​‏​
选项：
A: 0.04V
B: 0.06V
C: 0.08V
D: 0.12V
答案: 【 0.06V】

16、单选题：
‍The two input voltages of the differential amplifier are Ui1 = 0.04V ,and Ui2 = 0.08V, the differential mode input voltage .‎‍‎
选项：
A: 0.04V
B: 0.06V
C: 0.08V
D: 0.12V
答案: 【 0.04V】

17、单选题：
‎‌‎Typical differential amplifier circuit changes from double-ended output to single-ended output, common-mode voltage gain .‌‎‌
选项：
A: increase
B: decrease
C: unchanged
D: unable to determine
答案: 【  increase】

18、单选题：
‍Typical differential amplifier circuit changes from double-ended output to single-ended output, differential-mode voltage gain .‍‍‍
选项：
A: increase
B: decrease
C: unchanged
D: unable to determine
答案: 【 decrease】

19、单选题：
‎CMRR is a main technical index of differential amplifier circuit, reflects the ability of amplifier circuit.‌‎‌
选项：
A: eliminate distortion
B: high input resistance.
C: Enlarging Differential Mode and Suppressing Common Mode
D: low output resistance
答案: 【 Enlarging Differential Mode and Suppressing Common Mode】

20、单选题：
​Typical differential amplifier circuit changes from double-ended input to single-ended input, common-mode voltage gain .‏​‏
选项：
A: increase
B: decrease
C: unchanged
D: unable to determine
答案: 【  unchanged】

21、单选题：
​Typical differential amplifier circuit changes from double-ended input to single-ended input, differential-mode voltage gain .‌​‌
选项：
A: increase
B: decrease
C: unchanged
D: unable to determine
答案: 【 unchanged】

第十一章测验

1、单选题：

‏If the input voltage is 0.25 V and the output is -2.5 V, the value of Rf must be _______.

‎

‏

‎选项：
A: 40.0 kΩ
B: 20.0 kΩ
C: 16.0 kΩ
D: 5.0 kΩ
答案: 【 20.0 kΩ】

2、单选题：

‏The output voltage, VO, is given by ______.

​

‏

​选项：
A: VO =

B: VO =

C: VO =

D: None of the above
答案: 【 VO =
】

3、单选题：
‎A summing integrator is an op-amp integrator that has _______.‌‎‌
选项：
A: multiple feedback capacitors
B: multiple input resistors
C: multiple input resistors and feedback capacitors
D: None of the above
答案: 【  multiple input resistors and feedback capacitors】

4、单选题：
‍A second order low-pass filter has a high-end roll-off of _______. ‎‍‎
选项：
A: 60 dB/octave
B: 40 dB/decade
C: 20 dB/octave
D: 6 dB/decade
答案: 【  40 dB/decade】

5、单选题：
‍An active filter that provides a constant output for input signals above fol is called an ideal _______. ​‍​
选项：
A: low-pass filter
B: high-pass filter
C: bandpass filter
D: None of the above
答案: 【 high-pass filter】

6、单选题：
‏The voltage follower typically has a voltage gain value of _______.‌‏‌
选项：
A: 1000
B: 100
C: 10
D: 1
答案: 【 1】

7、单选题：

‏When the input voltage to this circuit is 0.25 V, the output voltage is _______

‍

‏

‍选项：
A: 10.0 V
B: 5.0 V
C: 3.0 V
D: 1.5 V
答案: 【 1.5 V】

8、单选题：

​When the input voltage to this circuit is 0.25 V, the output voltage is _______

‎

​

‎选项：
A: 10.0 V
B: 5.0 V
C: 3.0 V
D: 1.5 V
答案: 【 1.5 V】

9、单选题：

‌The operational amplifier circuit shown here is a(n) _______.

‌

‌

‌选项：
A: level comparator
B: differentiator
C: integrator
D: difference amplifier
答案: 【 integrator】

10、单选题：

‍The operational amplifier circuit shown here is a(n) _______.

‏

‍

‏选项：
A: level comparator
B: differentiator
C: integrator
D: difference amplifier
答案: 【 differentiator 】

11、单选题：
‌The CMRR of an inverting amplifier always lower than that of its op-amp because _______.‏‌‏
选项：
A: the common-mode gain of an op-amp increases when it is used in an inverting amplifier
B: the value of differential gain for an inverting amplifier is lower than that of its op-amp
C: slew-rate limiting decreases the common-mode gain of the op-amp
D: of the lower input impedance of the inverting amplifier
答案: 【  the value of differential gain for an inverting amplifier is lower than that of its op-amp】

12、单选题：
‌The op-amp circuit that add each input and multiplies the sum by a fixed amount is called a(n) ______. ‍‌‍
选项：
A: unity followe
B: integrator
C: differentiator
D: summing amplifier
答案: 【  summing amplifier】

13、单选题：
‌The op-amp circuit that has a capacitor as the feedback component is called a(n) ______. ​‌​
选项：
A: unity follower
B: integrator
C: differentiator
D: summing amplifier
答案: 【 integrator】

14、单选题：
​An op-amp integrator circuit has a 2 MΩ input resistor and a 5 μF feedback loop capacitor. If the inverting input voltage is 2 VDC, the final value of the output voltage is _______. ​​​
选项：
A: -20 V
B: -2 V
C: -0.2 V
D: 0.02 V
答案: 【 -0.2 V】

15、单选题：
‌Op-amp differentiator circuits differ from the integrators in that the differentiators ______. ​‌​
选项：
A: are not as useful
B: have a scale factor of -RC
C: have a resistor in the feedback loop
D: All of the above
答案: 【 All of the above】

16、单选题：
‎An inverting amplifier and a noninverting amplifier are built using the same values of Rf and R1. Assuming that the op-amps being used in the two circuits have identical common-mode gain values, _______.​‎​
选项：
A: the inverting amplifier has the higher CMRR
B: the noninverting amplifier has the higher CMRR
C: the CMRR is the same for the inverting and noninverting amplifiers
D: None of the above
答案: 【 the noninverting amplifier has the higher CMRR】

17、单选题：
​An inverting amplifier with +11 V supply voltages normally has a sinusoidal output of 10 VPP. When checking the circuit with an oscilloscope, you find that the output is 0 V. Which of the following could account for this problem? ‎​‎
选项：
A: R1 is open.
B: V1 = 0
C: R is shorted by a solder bridge.
D: All of the above
答案: 【 All of the above】

18、单选题：

‎ This op-amp is connected as a(n) _______.

‍

‎

‍选项：
A: inverting constant-gain multiplier
B: noninverting constant-gain multiplier
C: voltage buffer
D: None of the above
答案: 【 inverting constant-gain multiplier 】

19、单选题：

‍The voltage gain for this circuit is give as _______.

‎

‍

‎选项：
A: A = 1 +

B: A = -

C: A =

D: A = -

答案: 【 A = -
】

20、单选题：

‎Determine the gain of this circuit.

‎

‎

‎选项：
A: 10
B: 0.1
C: -0.1
D: -10
答案: 【  -10】

21、单选题：

​What is the design value for Rf?

‌

​

‌选项：
A: 60 Ω
B: 282 kΩ
C: 78.3 Ω
D: 180 kΩ
答案: 【  282 kΩ】

22、单选题：

‏If this circuit is to have an inverting voltage gain of 1, the ratio of Rf : R1 should be _______.

‌

‏

‌选项：
A: 1 : 1
B: 2 : 1
C: 1: 2
D: Cannot be done in theory. It can be done in practice by making R1 much larger than Rf.
答案: 【 1 : 1】

23、单选题：

‎This op-amp is connected as a(n) _______.

‌

‎

‌选项：
A: inverting constant-gain multiplier
B: noninverting constant-gain multiplier
C: voltage buffer
D: None of the above
答案: 【  noninverting constant-gain multiplier】

24、单选题：

‎The voltage gain for this circuit is given as _______.

‎

‎

‎选项：
A: A = 1 +

B: A = -

C: A = 1 +

D: A = -

答案: 【  A = 1 +
】

25、单选题：

‎ Determine the gain of this circuit.

‏

‎

‏选项：
A: 10
B: -10
C: 11
D: 1.1
答案: 【 11】

26、单选题：
‍A gain of 7 is required from a noninverting constant-multiplier op-amp circuit. If the input resistor is 5 k Ω, what should be the value of the feedback resistor ? ‏‍‏
选项：
A: 30 kΩ
B: 15 kΩ
C: 7.5 kΩ
D: 5 kΩ
答案: 【 30 kΩ】

27、单选题：

‍If this circuit is to have a voltage gain of 1, the ratio of Rf : R1 should be ______.

‏

‍

‏选项：
A: 1 : 1
B: 2 : 1
C: 1: 2
D: It can be done in practice by making R1 much larger than Rf.
答案: 【  It can be done in practice by making R1 much larger than Rf.】

28、单选题：

‎If the input voltage is 0.25 V and the required output voltage is 2.75 V, the value for Rf must be _______.

‎

‎

‎选项：
A: 40.0 kΩ
B: 20.0 kΩ
C: 10.0 kΩ
D: 5.0 kΩ
答案: 【 20.0 kΩ】

29、单选题：

‎The output voltage, VO, is given by _______.

‌

‎

‌选项：
A: VO =

B: VO =

C: VO =

D: None of the above
答案: 【 None of the above】

30、单选题：

‍For this cascade amplifier, the input voltage swing is 0.2 VPP. Calculate the peak-to-peak swing on the output voltage.

‏

‍

‏选项：
A: 9.6 VPP
B: 4.8 VPP
C: 2.4 VPP
D: 1.2 VPP
答案: 【 4.8 VPP】

31、单选题：
‏A second order high-pass filter has a low-end roll-off of ______.‎‏‎
选项：
A: 60 dB/octave
B: 40 dB/decade
C: 20 dB/octave
D: 6 dB/decade
答案: 【 40 dB/decade】

32、单选题：

‏This is a basic _______ circuit.

​

‏

​选项：
A: differentiator
B: integrator
C: two-input multiplier
D: subtractor
答案: 【  subtractor】

33、单选题：
‏How many feedback resistors are found in a 3-input voltage summing circuit that is constructed around an op-amp? ‌‏‌
选项：
A: 0
B: 1
C: 2
D: 3
答案: 【 1】

34、单选题：

‎This circuit is known as a _______.

‎

‎

‎选项：
A: noninverting amplifier
B: voltage buffer
C: low-pass filter
D: high-pass filter
答案: 【  voltage buffer】

35、单选题：
‍The output of an op-amp voltage buffer is characterized by _______.‌‍‌
选项：
A: VO = 1
B: VO = , where Rf = R1

C: VO =

D: VO = Vi
答案: 【 VO = Vi】

36、单选题：

‎If all resistances in this circuit are equal, the output is _______.

​

‎

​选项：
A: V1 - V2
B: V2 - V1
C: V1 + V2
D: V1 × V2
答案: 【 V2 - V1】

37、单选题：
‎An op-amp high-pass active filter provides a constant output _______.‌‎‌
选项：
A: from dc to foh
B: for all frequencies higher then fol
C: from fol to foh
D: from dc to infinite frequency
答案: 【 for all frequencies higher then fol 】

38、单选题：
‌An op-amp bandpass active filter provides a constant output _______.‎‌‎
选项：
A: from dc to foh
B: for all frequencies higher then fol
C: from fol to foh
D: from dc to infinite frequency
答案: 【 from fol to foh】

39、单选题：
‏The roll-off rate of a second order filter is _______.‏‏‏‏‏
选项：
A: 60 dB/decade or 18 dB/octave
B: 40 dB/decade or 12 dB/octave
C: 20 dB / decade or 6 dB/octave
D: 0 dB/decade or 0 dB/octave
答案: 【 40 dB/decade or 12 dB/octave】

40、单选题：
‎A constant-gain multiplier has three stages and a total gain of 22,200. For all three feedback resistors, Rf = 470 kΩ. Two of the R1 resistors have a value of 33 kΩ. What is the gain of the stage where R1 is unknown? ‏‎‏
选项：
A: 14.2
B: -14.2
C: 110.3
D: -110.3
答案: 【 110.3】

41、单选题：
‎A constant-gain multiplier has three stages and a total gain of 22,200. For all three feedback resistors, Rf = 470 kΩ. Two of the R1 resistors have a value of 33 kΩ. What is the value of the third R1, and what is the nature of its stage? ​‎​
选项：
A: 4.26 kΩ, ohms, inverting
B: 4.3 kΩ, ohms, noninverting
C: 4.3 kΩ, inverting
D: 4.6 kΩ, noninverting
答案: 【 4.3 kΩ, ohms, noninverting】

42、单选题：
​A constant-gain multiplier has three stages and a total gain of 22,200. For all three feedback resistors, Rf = 470 kΩ. Two of the R1 resistors have a value of 33 kΩ. What is the individual gain of the two identical stages where R1 is known? ‏​‏
选项：
A: 14.2
B: -14.2
C: 110.3
D: -110.3
答案: 【 -14.2】

43、单选题：
‎Which type of op-amp circuit has unity gain, no phase inversion, high input impedance, and low output impedance? ‎‎‎
选项：
A: voltage buffer
B: subtractor
C: summing amplifier
D: differentiator
答案: 【 voltage buffer】

44、单选题：
​An active filter that provides a constant output from dc to foh, and then passes no signal above foh, is called an ideal ______.‏​‏
选项：
A: low-pass filter
B: high-pass filter
C: bandpass filter
D: None of the above
答案: 【 low-pass filter】

45、单选题：
‍An active filter that provides a constant output for input signals from fol to foh is called an ideal _______.​‍​
选项：
A: low-pass filter
B: high-pass filter
C: bandpass filter
D: None of the above
答案: 【 bandpass filter】

第十二章中文测验

1、单选题：
输入信号只在半个周期内流过放大器件，这种工作方式称为▁▁▁放大。‏​‏
选项：
A: 甲类
B: 乙类
C: 甲乙类
D: 丙类
答案: 【 乙类】

2、单选题：
输入信号在整个周期都流过放大器件，这种工作方式称为▁▁▁放大。‏‌‏
选项：
A: 甲类
B: 乙类
C: 甲乙类
D: 丙类
答案: 【 甲类】

3、单选题：
‌甲乙类互补功率放大器能克服电路出现的       。‌‌‌
选项：
A: 零点漂移
B: 交越失真
C: 频率失真
D: 线性失真
答案: 【 交越失真】

4、判断题：
‍功率放大电路的电压放大倍数小于1，电流放大倍数大于1。（      ）​‍​
选项：
A: 正确
B: 错误
答案: 【 正确】

5、判断题：
在乙类功率放大器中，随着输入信号的幅度加大，放大器的输出功率‌‍和效率也是在一直地增大。（      ）‌‍‌
选项：
A: 正确
B: 错误
答案: 【 错误】

6、判断题：
乙类双电源互补对称功率放大器中，最大集电极功耗应发生在输出电压‎‎等于电源电压的0.6倍时。（      ）‎‎‎
选项：
A: 正确
B: 错误
答案: 【 正确】

7、判断题：
​乙类互补对称功率放大器中，效率最大时集电极功耗也最大。（     ）‏​‏
选项：
A: 正确
B: 错误
答案: 【 错误】

8、判断题：
‍乙类放大电路的工作效率比甲类高。（  ）​‍​
选项：
A: 正确
B: 错误
答案: 【 错误】

第十二章测验

1、单选题：
‍ A class B amplifier (not push-pull) _______.‌‍‌
选项：
A: conducts through 360° of the input waveform
B: conducts through 180° of the input waveform
C: conducts between 180° and 360° degrees of the input waveform, depending on the amount of dc bias
D: conducts through less than 180° of the input waveform
答案: 【  conducts through 180° of the input waveform 】

2、单选题：
‍ Crossover distortion in class B amplifiers is prevented by _______. ‌‍‌
选项：
A: biasing the transistors deeply into cutoff
B: biasing the transistors slightly above cutoff
C: using complementary-symmetry transistors
D: increasing the load resistance
答案: 【 biasing the transistors slightly above cutoff 】

3、单选题：
‏The maximum theoretical efficiency of an RC-coupled class A amplifier is ______. ​‏​
选项：
A: 25%
B: 50%
C: 78.5%
D: 99%
答案: 【 25%】

4、单选题：
‎The maximum possible efficiency of a class A amplifier is equal to _______‏‎‏
选项：
A: 30%
B: 25%
C: 20%
D: 15%
答案: 【 25%】

5、单选题：
​A class B push-pull amplifier _______. ‍​‍
选项：
A: conducts through 180° of the input waveform
B: conducts between 180° and 360° degrees of the input waveform, depending on the amount of dc bias
C: conducts through less than 180° of the input waveform
D: works only with digital and pulsed waveforms
答案: 【 conducts between 180° and 360° degrees of the input waveform, depending on the amount of dc bias】

6、单选题：
‏A class A amplifier ______.‍‏‍
选项：
A: conducts through 360° of the input waveform
B: conducts through 180° of the input waveform
C: conducts between 180° and 360° degrees of the input waveform, depending on the amount of dc bias
D: conducts through less than 180° of the input waveform
答案: 【 conducts through 360° of the input waveform】

7、单选题：
‍A class C amplifier _______.‌‍‌
选项：
A: conducts through 180° of the input waveform
B: conducts between 180° and 360° degrees of the input waveform, depending on the amount of dc bias
C: conducts through less than 180° of the input waveform
D: works only with digital and pulsed waveforms
答案: 【 conducts through less than 180° of the input waveform】

8、单选题：
‎Class C amplifiers are used mostly in ______ circuits.​‎​
选项：
A: audio
B: power amplifier
C: digital
D: tuned
答案: 【  tuned】

9、单选题：
‏A class D amplifier _______. ‏‏‏
选项：
A: conducts through 180° of the input waveform
B: conducts between 180° and 360° degrees of the input waveform, depending on the amount of dc bias
C: conducts through less than 180° of the input waveform
D: works only with digital and pulsed waveforms
答案: 【 works only with digital and pulsed waveforms】

10、单选题：
‍With transformer coupling the maximum theoretical efficiency of a class A amplifier can be increased up to _______.‎‍‎
选项：
A: 60%
B: 55%
C: 50%
D: 45%
答案: 【 50%】

11、单选题：
‏A class AB transistor amplifier using complementary transistors is biased by power supply that is ±18Vdc. The value of VCE(OFF) for either transistor is approximately equal to ______. ‍‏‍
选项：
A: 8 V
B: 10 V
C: 18 V
D: 36 V
答案: 【 18 V】

12、单选题：
‌Class D amplifiers have a maximum theoretical efficiency of _______.​‌​
选项：
A: 25%
B: 78.5%
C: 50%
D: over 90%
答案: 【 over 90%】

13、单选题：
​The crossover distortion in a class B amplifier is prevented by _______.‏​‏
选项：
A: biasing the individual transistors deeply into cutoff
B: biasing the transistors just slightly above cutoff
C: biasing the transistors just slightly into cutoff
D: adjusting the load resistance so that the transistor will turn on and off faster
答案: 【 biasing the transistors just slightly above cutoff】

14、单选题：
‏Class B amplifiers _______. ‏‏‏
选项：
A: provide an output signal for half the input signal cycle
B: usually contain an LC tank circuit in the BJT collector circuit
C: usually contain a single BJT that conducts through 360° of the ac input cycle
D: usually contain a single BJT that conducts through 270° of the ac input signal
答案: 【 provide an output signal for half the input signal cycle 】

15、单选题：
‌A class A amplifier has an 8 VPP output that is being applied to a 200 Ω load. What is the total ac load power? ​‌​
选项：
A: 320 mW
B: 640 mW
C: 40 mW
D: 80 mW
答案: 【 40 mW】

16、单选题：
​Impedance matching is important for ____. ‍​‍
选项：
A: maximum voltage transfer from source to load
B: maximum power transfer from source to load
C: maximum impedance transfer from source to load
D: maximum current transfer from source
答案: 【 maximum power transfer from source to load】

17、判断题：
‎Power amplifiers are typically used to drive low impedance loads.______‎‎‎
选项：
A: 正确
B: 错误
答案: 【 正确】

18、判断题：
‎The power that an amplifier delivers to a load is equal to the difference between the power that the circuit draws from the power supply and the power that the circuit dissipates. ​‎​
选项：
A: 正确
B: 错误
答案: 【 正确】

第十三章中文测验

1、单选题：
若要稳定输出电压，应该引入▁▁▁▁负反馈。‏‌‏
选项：
A: 电压
B: 电流
C: 串联
D: 并联
答案: 【 电压】

2、单选题：
‎负反馈所能抑制的干扰是▁▁▁▁。‍‎‍
选项：
A: 输入信号所包含的干扰
B: 反馈环内的干扰
C: 反馈环外的干扰
D: 不确定
答案: 【