专业英语Lesson+7+Basic+Knowledge+of+Transducers+and+Resistance+Transducers.ppt

1、Lesson 7 Basic Knowledge of Transducers and Resistance Transducers,Backgrounds Text tour Language in use Vocabulary Structure Reading/writing techniques,2020/9/21,1,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-induct

2、ance 互感 Paper backing 纸其 Resolution 分辩率,Backgrounds,2020/9/21,2,测控技术与仪器英语教程,Text tour,Outline 7.1 Transducer Elements 7.2 Transducer Sensitivity 7.3 Characteristics of an Ideal Transducer 7.4 Electrical Transducers 7.5 Resistance Transducers,2020/9/21,3,测控技术与仪器英语教程,7.1 Transducer Elements,A transduc

3、er is a device which converts the quantity being measured into an optical, mechanical, or-more commonly-electrical Fig7-1 Two-block-diagram representation of a typical transducer,2020/9/21,4,测控技术与仪器英语教程,7.2 Transducer Sensitivity,transducer sensitivity ：the relationship between the measurand and the

4、 transducer output signal is usually obtained by calibration tests :,2020/9/21,5,测控技术与仪器英语教程,7.2 Transducer Sensitivity,Example: Figure 7-2 Loaded spring of example 6.1,2020/9/21,6,测控技术与仪器英语教程,7.3 Characteristics of an Ideal Transducer,characteristics : ）high fidelity-the transducer output waveform

5、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 being placed exactly where it is needed. ）There should be a linear relationship between the measurand

6、 and the transducer signal.,2020/9/21,7,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 frequency of the transducer should be well separated from the frequency and harmonics of the measurand

7、.,2020/9/21,8,测控技术与仪器英语教程,7.4 Electrical Transducers,Electrical transducers can be divided into two distinct groups: variable-control-parameter types : ) resistance； ) capacitance； ）inductance； ） mutual-inductance types.,2020/9/21,9,测控技术与仪器英语教程,7.4 Electrical Transducers,b) self-generating types : )

8、 electromagnetic, ) thermoelectric, ）photoemissive, ） piezo-electric types.,2020/9/21,10,测控技术与仪器英语教程,7.5 Resistance Transducers,7.5.1 potentiometers 7.5.2 resistance strain gauges 7.5.3 Resistance Temperature Transducers 7.5.4 photoconductive cells 7.5.5 photoemissive cells,2020/9/21,11,测控技术与仪器英语教程,

9、7.5.1 Potentiometers,construction principles : Figure 7-3 Construction principles of resistance potentiometers,2020/9/21,12,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 voltage of the unload potentiometer circuit (b) (a) (b) Figure 7-4 Resolution effect

10、s and circuit diagram of resistance potentiometer,2020/9/21,13,测控技术与仪器英语教程,7.5.1 Potentiometers,the potentiometer causes the output/input graph Figure 7-5 Characteristic of a loaded potentiometer,2020/9/21,14,测控技术与仪器英语教程,7.5.1 Potentiometers,An analysis of the potentiometer circuit in the loaded con

11、dition,2020/9/21,15,测控技术与仪器英语教程,7.5.2 Resistance Strain Gauges,Resistance strain gauges are transducers which exhibit a change in electrical resistance in response to mechanical strain. a) bonded strain gauges: ) fine wire gauges cemented to paper backing ) photo-etched grids of conducting foil on a

12、n epoxy-resin backing, ) a single semiconductor filament mounted on an epoxy-resin backing with copper or nickel leads,2020/9/21,16,测控技术与仪器英语教程,7.5.2 Resistance Strain Gauges,unbonded strain gauges Figure 7-6 Unbonded strain gauges,2020/9/21,17,测控技术与仪器英语教程,7.5.3 Resistance Temperature Transducers,Re

13、sistance Temperature Transducers can be divided into two main groups: a) metal resistance temperature transducers Figure 7-7 Characteristics of a platinum resistance thermometer,2020/9/21,18,测控技术与仪器英语教程,7.5.3 Resistance Temperature Transducers,b) thermistor ( semiconductor) resistance temperature tr

14、ansducers Figure 7-8 Characteristics of thermistors,2020/9/21,19,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,2020/9/21,20,测控技术与仪器英语教程,7.5.5 Photoemissi

15、ve Cells,When light strikes the cathode of the photoemissive cell ,electrons are given sufficient energy to arrive the cathode. photoemissive voltage : Figure 7-11 Photoemissive cell,2020/9/21,21,测控技术与仪器英语教程,Vocabulary parameter, classified , external, generate, rotation Structure Reading/writing te

16、chniques,Language in use,2020/9/21,22,测控技术与仪器英语教程,Vocabulary,2020/9/21,23,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,2020/9/21,24,测控技术与仪器英语教程,parameter in text,This displacement may then be used to chan

17、ge an electrical parameter such as voltage, resistance, 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。,2020/9/21,25,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

18、的住房式样以及他们如何付房钱 an experimental school that keeps expanding the parameters of its curriculum. 一所不断扩展课程范围的实验学校,2020/9/21,26,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：,2020/9/21,27,测控技术与仪器英语教程,classified in text,Transducers are classified according to the trans

19、duction principle involved and the form of the measurand. 按照转换原理和测量形式对传感器进行分类。,2020/9/21,28,测控技术与仪器英语教程,classified in use,a classified document. 机密文件,2020/9/21,29,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

20、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：,2020/9/21,30,测控技术与仪器英语教程,external in text,The 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。,2020/9

21、/21,31,测控技术与仪器英语教程,external in use,external paints. 外用涂料 external 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,2020/9/21,32,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

22、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：通过命令计算机遵循用于代码段的给定参数来编制一个（程序),2020/9/21,33,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 .,2020/9/21,34,测控技术与仪器英语教程,generate in use,generate a discussion. 造成一场争论 generate heat. 产生热,2020/9/21,35,测控技