传感检测技术考试提纲 东南大学电子学院.docx

Required Contents for the Course No. 06043031Sensors and Measurement TechnologiesJune 2015Chapter 11. difference between the meaning of sensor and that of transducer.A transducer is a device that converts a signal from one physical form to a corresponding signal having a different physical form.Devices offering an electric output are called sensorssensor suggests the extension of our capacity to acquire information about physical quantities not perceived by human senses because of their subliminal nature or minuteness. Transducer implies that input and output quantities are not the same. A sensor may not be a transducer2. Static characteristics of sensors: Range, Accuracy, Repeatability, Precise, Sensitivity, Resolution, Threshold, Linearity, Hysteresis（磁滞现象）Range: Accuracy: how measuring results close to the true valueRepeatability:Precise:Sensitivity: the slope of the calibration curve, whether it is constant or not along the measurement range. 静态动态特性都要知道，下定义3. Power spectrum density of resistor thermal noise in case of open circuit and load matched.电阻热噪声，匹配和悬空负载的情况下，差一个44. Power spectrum density of flicker noise.1/F的噪声5. mathematical definition of dynamic error?下定义，用数学表达式6. What are the conditions for a signal transmitted through a linear system and remain undistorted? And what are the requirements on amplitude and phase frequency response of sensors in order to avoiding signal distortion?信号通过系统不失真的要求：幅频特性平坦，相频特性线性的7. The definition of rising time.上升时间定义8. How to calibrate a sensor.校准方法9. Failure rate, reliability, and mean time between failure（MTBF）.数学表达式要求会Chapter 2 and 31 Strain gage（应变计）1.1 Relation between stress and strain.杨氏模量1.2 Relation between resistance change and strain.一面三灵敏度的表达式？2 Resistive Temperature Detectors2.1 Temperature range of Pt RTD.-200度1000度/800度？超过800度就有升华，造成电阻敏感曲线变化，就不能用了。主要跟热电偶进行对比，热电偶升华没有影响，因为产生的是电势，所以热电偶能够测超过1000度的3 Measurement of resistance3.1 What is the advantage of 4-wire method?测电阻，万用表两线测，有电流电压降，4线可以避免电压降4 Accuracy of the balance measurement平衡探测优点，天平？5 What is the advantage of 3-wire Wheatstone bridge?电压降影响6 What are the advantages of difference measurement methods? Use mathematics to explain. 3条，灵敏度提高，偶次非线性，抑制共模干扰，数学推导7 What advantage can average measurement bring to signal to noise ratio in condition of white noise?平均，提高信噪比，特别对于白噪声，对于方差的影响，1/n关系8 What advantages do AC power supplied Wheatstone bridge have over DC power supplied bridge.直流电桥有flicker noise，会漂移，交流电桥没有；直流电桥，流过不同金属，有个寄生的thermal couple热电偶的热电势，交流电桥刚好可以把两个周期里的抵消掉9 The relation between resistance and temperature of negative coefficient thermistors.Thermistor电阻温度关系，负温度系数，RT=a exp（B/T）？作业做过的，19.8那题10 Determine the maximum current or dropping voltage on NTC thermistors considering thermal dissipation and certain accuracy.给温度测量范围，问，最大容许工作电流11 What is the poisoning effect of gas sensors?气体传感器中毒，被测气体浓度太高，有一个差分时间12 What is the cross sensitivity of gas sensors?交叉敏感度Chapter 4 and 51 What is the fringe effect of capacitance sensor? How to resolve this problem?电容传感器边缘效应，加保护环解决，保护环要和信号接在同一个点位上2 What is the advantage of transformer bridges over Wheatstone bridges with resistance balance arms?电阻做平衡臂，寄生电容改变电桥的灵敏度，用变压器电桥就不会有这样的问题3 Theory and operation principle of phase sensitive demodulation of AC Wheatstone bridges? And the aim of it is to detect the sign of measurand.不能用普通检波，要用相频检波，判断被测量的符号是正还是负，给相频检波电路图，要会说工作原理4 What are the advantages of coherent demodulation for AC supplied Wheatstone bridges?相干探测优点，用于交流场合，不在低频直流处，没有flicker noise，没有低频漂移，另外通过限制噪声带宽，使得总的噪声功率降低，有比较好的信噪比5 Operation principle of Pulse width modulation (PWM) circuits for capacitive sensors.描述工作过程，会画各个信号的时序图（已知电路图，C1C2）6 Signal conditioning circuit for differential self inductive sensors. (AC Wheatstone Bridge)知道，会叙述差分惠斯通电桥对这个7 Principle of eddy current sensor. Oscillating while no conductive targets is nearby. Off oscillating and lower amplitude output while approaching conductive targets.没有导体靠近是谐振的，谐振峰很尖，有任何一个导体靠近，很敏感，就失谐了，Q值高的原因，等效自感的变化使电路失去谐振8 Hall effect and sensors. How to limit temperature interference?霍尔传感器，知道怎么样去限制温度的影响，工作电流也有限制Chapter 6 and 71 Definition of Seebeck effect, Peltier effect and Thompson effect and their relation.几个效应，相互关系，数学表达式2 Advantages of thermal couplers.课件列出来了3 Different kind of thermal couplers and their specified application.高温、低温、常温等场合4 Calculate measure-junction temperature while the reference junction is not at 0C according to standard voltage-temperature table for thermal couplers.参考温度不是0，给了热电势，要算被测量点的温度，J型热电偶，作业题5 Advantage of differential detection circuit for photovoltaic sensors? one shielded for reference and the other exposed to light for measurement. Answer: Compensation for temperate variation.光电传感器，二极管是光电二极管，有温漂，用差分方式，感受被测量，又要用遮光罩，6 Theory of piezoelectric effect, coupled equation.压电传感器的耦合方程7 Frequency response of piezoelectric accelerometer, reasons for low frequency loss and high frequency resonance and. Frequency band for acceleration measurement.压电传感器，低频noise是因为有漏电阻，高频谐振是因为内部的机械阻尼很小，产生机械谐振，在中间幅度平坦的区域工作8 Theory of electrometer amplifier for piezo-sensors, equivalent circuit, influence of cable on electrometer amplifier.电压放大器，电荷放大器，等效电路，电感的杂散电容对电压放大器有影响， 9 Theory of charge amplifier for piezo-sensors, equivalent circuit, influence of cable, influence of feedback capacitance on sensitivity, how to suppress the influence of input offset current and voltage of amplifier. 对电荷放大器在放大倍数比较高的时候是没什么影响的，并联电阻消除放大器的输入偏执电流和偏置电压10 Frequency response of pyroelectric sensor.低频高频都不能通过，以很慢的速度靠近是不会响应的Chapter 81 Theory of movement direction detection circ