大学MOOC Experiment of Electrical Technology(Beihang University)1459019161 最新慕课完整章节测试答案

Chapter Test

1、单选题：
‎The safety voltage for continuous contact with human body is not higher than () V, and the safety current is not higher than () mA.‍
选项：
A: 12, 5
B: 24, 10
C: 36, 15
D: 48, 20
答案: 【 24, 10】

2、多选题：
‏In order to improve the effectiveness of classroom experiments, which of the following items shall be done: ()​
选项：
A: Before the experiment, a measurement data sheet should be designed and the number and interval of measuring points reasonably selected. If the data to be measured is on the curved part of a curve, more measuring points should be arranged whereas fewer points are required on the smooth part. In this way, better results can be obtained from curve fitting in subsequent data processing.
B: Continuity test shall be conducted on the conductor before overlapping the circuit.
C: Usually, the "loop connection method" is adopted through sequential wiring from the power supply until the whole circuit is completed.
D: For a more complex circuit, it shall be divided into several independent sub-circuits according to its functions and completed step by step.
答案: 【 Before the experiment, a measurement data sheet should be designed and the number and interval of measuring points reasonably selected. If the data to be measured is on the curved part of a curve, more measuring points should be arranged whereas fewer points are required on the smooth part. In this way, better results can be obtained from curve fitting in subsequent data processing.;
Continuity test shall be conducted on the conductor before overlapping the circuit.;
Usually, the "loop connection method" is adopted through sequential wiring from the power supply until the whole circuit is completed.;
For a more complex circuit, it shall be divided into several independent sub-circuits according to its functions and completed step by step.】

3、多选题：
‏In the experiment class, which of the following measures shall be taken to protect against electric shock: ()‌
选项：
A: Do not place drinks, cups and other items on the experiment table.
B: Do not touch experiment devices, instruments and equipment with wet hands.
C: Connect the circuit on an insulation pad carefully according to the circuit diagram, and check it after it is connected. If necessary, ask the teacher to recheck it to ensure that it is correct before switching on the power supply. If it is necessary to change or disconnect the line during the experiment, cut off the power supply before performing any operation.
D: If any abnormal phenomena arise during the experiment such as heating, luminescence, sound and smell, cut off the power supply immediately, report to the teacher and identify the cause to prevent failure propagation.
答案: 【 Do not place drinks, cups and other items on the experiment table.;
Do not touch experiment devices, instruments and equipment with wet hands.;
Connect the circuit on an insulation pad carefully according to the circuit diagram, and check it after it is connected. If necessary, ask the teacher to recheck it to ensure that it is correct before switching on the power supply. If it is necessary to change or disconnect the line during the experiment, cut off the power supply before performing any operation.;
If any abnormal phenomena arise during the experiment such as heating, luminescence, sound and smell, cut off the power supply immediately, report to the teacher and identify the cause to prevent failure propagation.】

4、多选题：
‍In the experiment class, in case of an electric shock accident, which of the following measures shall be taken: ()‎
选项：
A: The first thing is to ensure the safety of the rescuers themselves.
B: Then disconnect the person who gets an electric shock from the power supply. The most effective way to do this is to directly close the switch and cut off the power supply.
C: Insulating objects such as dry wooden sticks shall be used to separate the electric shock victim from the power source.
D: Call the 120 first-aid phone number at once and adopt artificial respiration in case of emergency. Then call Beihang University Alarm Center at 82317119.
答案: 【 The first thing is to ensure the safety of the rescuers themselves.;
Then disconnect the person who gets an electric shock from the power supply. The most effective way to do this is to directly close the switch and cut off the power supply.;
Insulating objects such as dry wooden sticks shall be used to separate the electric shock victim from the power source.;
Call the 120 first-aid phone number at once and adopt artificial respiration in case of emergency. Then call Beihang University Alarm Center at 82317119.】

5、多选题：
‌The main causes of electric fires include: ()‌
选项：
A: Electric leakage
B: Short circuit
C: Excess load
D: Excessive contact resistance
答案: 【 Electric leakage;
Short circuit;
Excess load;
Excessive contact resistance】

6、多选题：
‌Which of the following shall be used for extinguishing electric fire: ()​
选项：
A: Water
B: Carbon-dioxide (fire) extinguisher
C: Foam fire extinguisher
D: Powder fire extinguisher
答案: 【 Carbon-dioxide (fire) extinguisher;
Powder fire extinguisher】

Chapter Test

1、单选题：
‍The basic component of a combinational logic circuit is: ().‎
选项：
A: Gate circuit
B: Flip-flop
C: Operational amplifier
D: Register and capacitor
答案: 【 Gate circuit】

2、单选题：
‏When debugging a combinational logic circuit, the high and low levels shall satisfy: ().‍
选项：
A: High level > 3V, low level < 1V;
B: High level > 3V, low level < 0.4V;
C: High level > 4V, low level < 0.4V;
D: All of the above are acceptable.
答案: 【 High level > 3V, low level < 0.4V;】

3、判断题：
‎Sequential logic circuit has an output signal that depends only on the current input signal and is independent of the state of the circuit. ()​
选项：
A: 正确
B: 错误
答案: 【 错误】

4、判断题：
​The preset terminal and reset terminal of D flip-flop can be valid at the same time. ()‌
选项：
A: 正确
B: 错误
答案: 【 错误】

5、判断题：
​In sequential logic circuits, after the rising edge of the clock arrives, the input signal will remain stable for a period of time, which is called hold time. ()‎
选项：
A: 正确
B: 错误
答案: 【 正确】

6、判断题：
‏Static debugging and dynamic debugging methods can be used to debug sequential logic circuits. ()​
选项：
A: 正确
B: 错误
答案: 【 正确】

Chapter Test

1、单选题：

‍Negative half-cycle distortion occurs in the output waveform of the common-emitter amplifier because: ().

‎

‍

‎选项：
A: The Quiescent point is low leading to cut-off distortion.
B: The Quiescent point is low leading to saturation distortion.
C: The Quiescent point is high leading to cut-off distortion.
D: The Quiescent point is high leading to saturation distortion.
答案: 【 The Quiescent point is high leading to saturation distortion.】

2、单选题：
​The phase difference between the input voltage and the output voltage of the common-emitter amplifier is: ().‏
选项：
A: 0°
B: 45°
C: 90°
D: 180°
答案: 【 180°】

3、多选题：
‌Which of the following feedback can increase the input resistance? ()‏
选项：
A: Voltage - parallel negative feedback
B: Voltage - series negative feedback
C: Current - parallel negative feedback
D: Current - series negative feedback
答案: 【 Voltage - series negative feedback;
Current - series negative feedback】

4、多选题：
​Which of the following feedback can reduce the output resistance? ()​
选项：
A: Voltage - parallel negative feedback
B: Voltage - series negative feedback
C: Current - parallel negative feedback
D: Current - series negative feedback
答案: 【 Voltage - parallel negative feedback;
Voltage - series negative feedback】

5、判断题：
‏The measurement of dynamic parameters of the amplifier must be carried out in the absence of distortion. If there is signal distortion, effort must be made to eliminate the distortion according to the specific situation of the distortion before performing dynamic parameter test. ()‍
选项：
A: 正确
B: 错误
答案: 【 正确】

6、判断题：

​For the common-emitter amplifier as shown in the figure, when the Quiescent point is low leading to cut-off distortion, the resistance value of potentiometer RW shall be reduced in order to eliminate the distortion. ()

‏

​

‏选项：
A: 正确
B: 错误
答案: 【 正确】

7、判断题：
‎Negative feedback can increase the amplification of the amplifier. ()​
选项：
A: 正确
B: 错误
答案: 【 错误】

Chapter Test

1、单选题：
‍555 timer is a ().‍
选项：
A: Digital integrated circuit
B: Analog-digital hybrid integrated circuit
C: Analog integrated circuit
D: None of the above is true
答案: 【 Analog-digital hybrid integrated circuit】

2、单选题：
‍The application of 555 timer does not include ().‎
选项：
A: Delay and timing
B: Signal amplification
C: Pulse shaping
D: Pulse generation
答案: 【 Signal amplification】

3、单选题：
‌The waveform that a multivibrator composed of 555 timer can generate is ().‎
选项：
A: Sinusoidal Wave
B: Triangular wave
C: Irregular waveform
D: Rectangular wave
答案: 【 Rectangular wave】

4、单选题：

‌The width (T) of output pulse from a monostable flip-flop composed of 555 is ().

‎

‌

‎选项：
A: T=1.3RACt
B: T=1.5 RACt
C: T=0.9 RACt
D: T=1.1 RACt
答案: 【 T=1.1 RACt】

5、单选题：

‌The maximum value of VC measured in the monostable flip-flop composed of 555 timer is: ().

‌

‌

‌选项：
A: 2/3VCC
B: 1/2 VCC
C: VCC
D: 1/3 VCC
答案: 【 2/3VCC】

6、判断题：
‍Under the effect of the trigger signal from the monostable flip-flop the circuit turns over from the steady state to the transient stable state where it stays for some time, and then automatically returns to the steady state. ()‏
选项：
A: 正确
B: 错误
答案: 【 正确】

7、判断题：
​The high-level width and low-level width of the rectangular wave generated by a multivibrator composed of 555 timer are equal. ()‌
选项：
A: 正确
B: 错误
答案: 【 错误】

8、判断题：
‏The comparison voltages of comparators C1 and C2 are 2/3VCC and 1/3VCC respectively only when Pin 5 of 555 timer is suspended, that is, when the applied control voltage is 0. ()​
选项：
A: 正确
B: 错误
答案: 【 正确】

Chapter Test

1、单选题：
‌When the 74LS90 chip QA is connected to INPUT B and the counting pulse is input from INPUT A, which counting system does the chip employ? ()‍
选项：
A: Binary system
B: Quinary system
C: Decimal system
D: Septenary system
答案: 【 Decimal system】

2、单选题：
​If the input signal frequency of CD4060 Pin 11 is 100kHz, then the output signal frequency of its Pin 15 (2^10 frequency division) is: ().‌
选项：
A: 50kHz
B: 10kHz
C: 5kHz
D: 97.66Hz
答案: 【 97.66Hz】

3、多选题：
‌If each time the switch of the single pulse generator is pressed, the count displayed by the digital tube differs greatly. What are possible causes? ().‍
选项：
A: The frequency of the measured signal is unstable.
B: The width of gating signal is unstable.
C: The gate circuit has no output.
D: All of the above are possible.
答案: 【 The frequency of the measured signal is unstable.;
The width of gating signal is unstable.】

4、判断题：
‏The priority of setting 74LS90 chip to 0 is higher than that of setting it to 9. ()​
选项：
A: 正确
B: 错误
答案: 【 错误】

5、判断题：
​There is no difference between the two pins of a passive crystal oscillator. ()‍
选项：
A: 正确
B: 错误
答案: 【 正确】

6、判断题：
‍The width of the gating signal generated by a single pulse generator depends on the length of time the switch is pressed. ()‎
选项：
A: 正确
B: 错误
答案: 【 错误】

Chapter Test

1、单选题：

‌Which characteristics curve in the figure is a output characteristics curve of the voltage source with negative internal resistance? ()

‌

‌

‌选项：
A: Curve 1
B: Curve 2
C: Curve 3
D: All of the above
答案: 【 Curve 3】

2、单选题：
‏When RC series circuit is connected to DC power supply, what measures shall be taken to speed up the transient process? ()‎
选项：
A: Reduce resistance R
B: Increase resistance R
C: Increase the supply voltage
D: Increase capacitor
答案: 【 Reduce resistance R】

3、单选题：

‎For the RLC series circuit as shown in the figure, initial conditions are uc(0)=0 and i(0)=0. When R<0, the waveform of uc(t) is: ()

‏

‎

‏选项：
A:
B:
C:
D:
答案: 【 】

4、单选题：

‍In the RC series circuit shown in the figure, switch S is at terminal 2 and stable. When t=0 and switch S is connected from 2 to 1, the circuit response is: ()

‍

‍

‍选项：
A: Zero input response
B: No response
C: Zero state response
D: None of the above is true
答案: 【 Zero state response】

5、判断题：
​The bleeder circuit is followed by a voltage follower so as to improve the carrying capacity. ()‏
选项：
A: 正确
B: 错误
答案: 【 正确】

6、判断题：
‍For the zero-state response and zero-input response of RC first-order circuit, the capacitor voltage can reach a stable value only when t→∞ in theory. But uc is close to the stable value after (3-5) τ. This can be considered as the end of the transient process in engineering practice. ()‏
选项：
A: 正确
B: 错误
答案: 【 正确】

Chapter Test

1、单选题：
‍When the reset terminal of shift register 74LS194 is connected to high level, S1 and S0 are connected to "1" and "0" respectively, and the rising edge occurs at the clock terminal, the function fulfilled by the chip is: ()‍
选项：
A: Reset
B: Move to the left
C: Move to the right
D: Hold
答案: 【 Move to the left】

2、单选题：

‍In the following parallel input-serial output circuit, if d0 to d7 are connected to "0 1 0 1 0 1 0 1", then after 7 clock periods, the state of output terminals Q0 to Q7 is: ()

‌

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