测控专业英语第七课

1、Lesson 7 Basic Knowledge of Transducers and Resistance Transducers Backgrounds Text tour Language in use Vocabulary 2021-10-161测控技术与仪器英语教程 Terminology Cement 粘接剂 Coefficient 系数 Diaphragm 振动膜 Inductance 电感 Life expectancy 概率寿命 Natural frequency 固有频率 Mutual-inductance 互感 Paper backing 纸基 Resolution 分辩

2、率Backgrounds2021-10-162测控技术与仪器英语教程Text tour Outline 7.1 Transducer Elements7.2 Transducer Sensitivity 7.3 Characteristics of an Ideal Transducer 7.4 Electrical Transducers 7.5 Resistance Transducers2021-10-16171测控技术与仪器英语教程7.1 Transducer Elements A transducer is a device which converts the quantity b

3、eing measured into an optical, mechanical, or-more commonly-electrical signal. Fig7-1 Two-block-diagram representation of a typical transducerSensingelementconversionorcontrolelementprimarysignalormeasurandtransduceroutput signalsecondarysignal2021-10-16172测控技术与仪器英语教程7.2 Transducer Sensitivity trans

4、ducer sensitivity ：the relationship between the measurand and the transducer output signal is usually obtained by calibration tests :incrementmeasurandincrementsignaloutputK12021-10-16273测控技术与仪器英语教程7.2 Transducer Sensitivity Example:Figure 7-2 Loaded spring of example 6.12021-10-16274测控技术与仪器英语教程7.3

5、Characteristics of an Ideal Transducercharacteristics :）high fidelity-the transducer output waveform shape be a faithful reproduction of the measurand; there should be minimum distortion. ）There should be minimum interference with the quantity being measured ）Size. The transducer must be capable of

6、being placed exactly where it is needed.）There should be a linear relationship between the measurand and the transducer signal.2021-10-16275测控技术与仪器英语教程7.3 Characteristics of an Ideal Transducer ）The transducer should have minimum sensitivity to external effects, pressure transducers ）The natural fre

7、quency of the transducer should be well separated from the frequency and harmonics of the measurand.2021-10-16276测控技术与仪器英语教程7.4 Electrical TransducersElectrical transducers can be divided into two distinct groups:a)variable-control-parameter types : ) resistance； ) capacitance； ）inductance； ） mutual

8、-inductance types.2021-10-16520测控技术与仪器英语教程7.4 Electrical Transducersb) self-generating types : ) electromagnetic, ) thermoelectric, ）photoemissive, ） piezo-electric types.2021-10-16521测控技术与仪器英语教程7.5 Resistance Transducers7.5.1 potentiometers7.5.2 resistance strain gauges7.5.3 Resistance Temperature

9、Transducers7.5.4 photoconductive cells7.5.5 photoemissive cells 2021-10-16522测控技术与仪器英语教程7.5.1 Potentiometers construction principles :Figure 7-3 Construction principles of resistance potentiometers2021-10-16523测控技术与仪器英语教程7.5.1 Potentiometers the contact moves from one wire to next (a) and the output

10、 voltage of the unload potentiometer circuit (b) (a) (b)Figure 7-4 Resolution effects and circuit diagram of resistance potentiometer2021-10-16524测控技术与仪器英语教程7.5.1 Potentiometersthe potentiometer causes the output/input graph Figure 7-5 Characteristic of a loaded potentiometer11Vv0gincreRRLTsin2021-1

11、0-16525测控技术与仪器英语教程7.5.1 PotentiometersAn analysis of the potentiometer circuit in the loaded condition 10)1 (TiLTiTxxRRxxvv2021-10-16526测控技术与仪器英语教程7.5.2 Resistance Strain GaugesResistance strain gauges are transducers which exhibit a change in electrical resistance in response to mechanical strain.

12、a) bonded strain gauges: ) fine wire gauges cemented to paper backing ) photo-etched grids of conducting foil on an epoxy-resin backing, ) a single semiconductor filament mounted on an epoxy-resin backing with copper or nickel leads 2021-10-16527测控技术与仪器英语教程7.5.2 Resistance Strain Gaugesb)unbonded st

13、rain gaugesFigure 7-6 Unbonded strain gauges2021-10-16528测控技术与仪器英语教程7.5.3 Resistance Temperature TransducersResistance Temperature Transducers can be divided into two main groups: a) metal resistance temperature transducersFigure 7-7 Characteristics of a platinum resistance thermometer)(1 0101 RRC0t

14、emparature( )R(ohms)0R1R3Rtempernture( )resistance changeC0C02021-10-16529测控技术与仪器英语教程7.5.3 Resistance Temperature Transducers b) thermistor ( semiconductor) resistance temperature transducersFigure 7-8 Characteristics of thermistorstype 1type 3type 21031051041021050100resistance(ohms)(log scale)Temp

15、erature)(0C2021-10-16530测控技术与仪器英语教程7.5.4 Photoconductive Cells The resistance between the metal electrodes decrease as the intensity of the light striking the semiconductor increases.Figure 7-9 Photoconductive cell 2021-10-16531测控技术与仪器英语教程7.5.5 Photoemissive Cells When light strikes the cathode of t

16、he photoemissive cell ,electrons are given sufficient energy to arrive the cathode. photoemissive voltage : Figure 7-11 Photoemissive cellLpRIv 02021-10-16532测控技术与仪器英语教程 Vocabulary parameter, classified , external, generate, rotation Structure Reading/writing techniquesLanguage in use2021-10-16533测控

17、技术与仪器英语教程Vocabulary2021-10-16534测控技术与仪器英语教程parameter in dictionary 参数，参量：在相同一般类型的等式中取值变化的等式中的常数或常量，尤其是曲线方程和平面方程中能代表一类曲线或平面的常量 限制因素：限定可能性和结果的因素 决定变数范围的要素，范围，界限：决定变化范围的因素；限度2021-10-16535测控技术与仪器英语教程parameter in text This displacement may then be used to change an electrical parameter such as voltage, r

18、esistance, capacitance, or inductance. 然后位移可以改变电参数，如电压、电阻、电容或者感应系数。 2021-10-16536测控技术与仪器英语教程Parameter in use all the parameters of shelterwhere people will live, what mode of housing they will choose, and how they will pay for it 住宿的所有限制因素人们住在哪里、他们将选择什么样的住房式样以及他们如何付房钱 an experimental school that kee

19、ps expanding the parameters of its curriculum. 一所不断扩展课程范围的实验学校2021-10-16537测控技术与仪器英语教程classified in dictionary 分门别类的：划分到阶级或类别中的 机密的，保密的：只提供给获得授权的人的，如因国家安全的原因：2021-10-16538测控技术与仪器英语教程classified in text Transducers are classified according to the transduction principle involved and the form of the mea

20、surand. 按照转换原理和测量形式对传感器进行分类。 2021-10-16539测控技术与仪器英语教程classified in use a classified document. 机密文件2021-10-16540测控技术与仪器英语教程external in dictionary 外面的，外在的：与外面或外部有关的，出现在外面或外部的，与外面或外部有联系的；外部的 外用的：适于外面使用的： 客观的，物质的：与精神无关的 外界的：存在或来自于外界或外面的： 外表的，外观的：外表的，主要和外表有关的；表面的： 外国的，国际的：外国的事务或外国的，与其有关的：2021-10-16541测控技

21、术与仪器英语教程external in textThe transducer should have minimum sensitivity to external effects, pressure transducers, for example, are often subjected to external effects such vibration and temperature. 传感器对外部影响的灵敏度应该小，例如压力传感器经常受到外部振动和温度的影响。2021-10-16542测控技术与仪器英语教程external in use external paints. 外用涂料 e

22、xternal pressures. 外界的压力 An internal sense of righteousness dwindles into an external concern for reputation 内心的正义感变成对外在名誉的关心 the countrys minister of external affairs. 该国的外交部长2021-10-16543测控技术与仪器英语教程generate in dictionary 形成，造成： 产生物理反应：作为化学或物理变化过程的结果而产生 产生（后代）；生育 形成（几何图形）：用画曲线或面来作出（一个几何图形） 生成，产生：通过

23、命令计算机遵循用于代码段的给定参数来编制一个（程序)2021-10-16544测控技术与仪器英语教程generate in text Electrical noise may be generated by variation in contact resistance , by mechanical wear due to contact friction, and by contact vibration transmitted from the sensing element. 电子噪声可以通过接触电阻的振动、触头摩擦形成的机械磨损以及从敏感元件传出的触头振动产生 .2021-10-16545测控技术与仪器英语教程generate in use generate a discussion. 造成一场争论