pn基本电工仪表的使用及测量误差的计算.doc
《pn基本电工仪表的使用及测量误差的计算.doc》由会员分享,可在线阅读,更多相关《pn基本电工仪表的使用及测量误差的计算.doc(56页珍藏版)》请在三一文库上搜索。
1、、实验目的1.熟悉实验台上各类电源及各类测量仪表的布局和使用方法。2.掌握指针式电压表、电流表内阻的测量方法。3.熟悉电工仪表测量误差的计算方法。二、原理说明1.为了准确地测量电路中实际的电压和电流,必须保证仪表接入电路后不会改变被测电路的工作状态。这就要求电压表的内阻为无穷大;电流表的内阻为零。而实际使用的指针式电工仪表都不能满足上述要求。因此,当测量仪表一旦接入电路,就会改变电路原有的工作状态,这就导致仪表的读数值与电路原有的实际值之间出现误差。这种测量误差值的大小与仪表本身内阻值的大小密切相关。只要测出仪表的内阻,即可计算出由其产生的测量误差。以下介绍几种测量指针式仪表内阻的方法。2.用
2、“分流法”测量电流表的内阻如图3-1-1所示。为被测内阻()的直流电流表。测量时先断开开关,调节电流源的输出电流使表指针满偏转。然后合上开关,并保持值不变,调节电阻箱的阻值,使电流表的指针指在满偏转位置,此时有为固定电阻器之值,可由电阻箱的刻度盘上读得。3.用分压法测量电压表内阻。如图3-1-2所示。为被测内阻()的电压表。测量时先将开关闭合,调节直流稳压电源的输出电压,使电压表的指针为满偏转。然后断开开关,调节使电压表的指针值减半。此时有:电压表的灵敏度为:。式中为电压表满偏时的电压值。4.仪表内阻引入的测量误差(通常称之为方法误差,而仪表本身结构引入的误差称为仪表基本误差)的计算。(1)以
3、图3-1-3所示电路为例,上的电压为,若,则现用一内阻为的电压表来测量值,当与并联后,以此来替代上式中的,则得绝对误差为化简后得若,则得相对误差由此可见,当电压表的内阻与被测电路的电阻相近时,测得值的误差是非常大的。(2)伏安法测量电阻的原理为:测出流过被测电阻的电流及其两端的电压降,则其阻值。图3-1-4()、()为伏安法测量电阻的两种电路。设所用电压表和电流表的内阻分别为,电源,假定的实际值为。现在来计算用此两电路测量结果的误差。电路():相对误差电路():相对误差由此例,既可看出仪表内阻对测量结果的影响,也可看出采用正确的测量电路也获得较满意的结果。三、实验设备表3-1-1序 号名 称型
4、号与规格数 量备 注1可调直流稳压电源0-30v二路2可调恒流源0-50mA13指针式万用表1自备4可调电阻箱0-9999.915电阻器按需选择四、实验内容1.根据“分流法”原理测定指针式万用表(型或其他型号)直流电流和档量限的内阻。线路如图3-1-1所示。可选用中的电阻箱(下同)。表3-1-2被测电流量限断开时的表读数闭合时的表读数计算内阻2.根据“分压法”原理按图3-1-2接线,测定指针式万用表直流电压和档量限的内阻。表3-1-3被测电压表量限闭合时表读数断开时表读数计算内阻3.用指针式万用表直流电压档量程测量图3-1-3电路中的电压之值,并计算测量的绝对误差与相对误差。表3-1-4计算值
5、实测值绝对误差相对误差五、实验注意事项1.实验台上配有实验所需的恒流源,在开启电源开关前,应将恒流源的输出粗调拨到档,输出细调旋钮应调至最小。按通电源后,再根据需要缓慢调节。2.当恒流源输出端接有负载时,如果需要将其粗调旋钮由低档位向高档位切换时,必须先将其细调旋钮调至最小。否则输出电流会突增,可能会损坏外接器件。3.实验前应认真阅读直流稳压电源的使用说明书,以便在实验中能正确使用。4.电压表应与被测电路并联使用,电流表应与被测电路串联使用,并且都要注意极性与量程的合理选择。5.本实验仅测试指针式仪表的内阻。由于所选指针的型号不同,本实验中所列的电流、电压量程及选用的、等均会不同。实验时请按选
6、定的表型自行确定。六、思考题1.根据实验内容1和2,若已求出档和档的内阻,可否直接计算得出档和档的内阻?2.用量程为的电流表测实际值为的电流时,实际读数为,求测量的绝对误差和相对误差。七、实验报告1.列表记录实验数据,并计算各被测仪表的内阻值。2.计算实验内容3的绝对误差与相对误差。3.对思考题的计算。4.其他(包括实验心得、体会及意见等)。(英文版 ) Two regulations promulgated for implementation is in the party in power for a long time and the rule of law conditions, t
7、he implementation of comprehensive strictly strategic plan, implementation in accordance with the rules and discipline to manage the party, strengthen inner-party supervision of major initiatives. The two regulations supporting each other, the adhere to a positive advocate, focusing on morality is o
8、f Party members and Party leading cadres can see, enough to get a high standard; around the party discipline, disciplinary ruler requirements, listed as negative list, focusing on vertical gauge, draw the party organizations and Party members do not touch the bottom line . Here, the main from four s
9、quare face two party rules of interpretation: the first part introduces two party Revised regulations the necessity and the revision process; the second part is the interpretation of the two fundamental principles of the revision of laws and regulations in the party; the third part introduces two pa
10、rty regulations modified the main changes and needs to grasp several key problems; the fourth part on how to grasp the implementation of the two regulations of the party. and revised the necessity and revised history of the CPC Central Committee the amendment to the Chinese Communist Party members a
11、nd leading cadres honest politics several guidelines and column 1 by 2015 to strengthen party laws and regulations focus. Two party regulations revision work lasted a Years, pooling the wisdom of the whole party, ideological consensus, draw historical experience, respect for the wisdom of our predec
12、essors, which reflects the unity of inheritance and innovation; follow the correct direction, grasp the limited goals, adhere to the partys leadership, to solve the masses of the people reflect a focus on the problem. The new revision of the and , reflects the partys 18 and the eighth session of the
13、 third, the spirit of the fourth plenary session, reflecting the experience of studying and implementing the General Secretary Xi Jinping series of important speech, reflects the partys eighteen years comprehensive strictly practice. (a) revised two regulations of the party need of in based on revis
14、ed, the promulgation and implementation of January 2010, to strengthen the construction of the contingent of leading cadres play an important role. But with the party to manage the party strictly administering the deepening, has not been able to fully meet the actual needs. Content is too complicate
15、d, eight prohibition, 52 are not allowed to hard to remember, and also difficult to put into practice; the second is concisely positive advocated by the lack of prohibited provisions excessive, no autonomy requirements; the third is banned terms and discipline law, both with the party discipline, di
16、sciplinary regulations repeat and Criminal law and other laws and regulations repeat; the fourth is to clean the theme is not prominent, not for the existing problems, and is narrow, only needle of county-level leading cadres above. is in 1997 based on revision, in December 2003 the promulgation and
17、 implementation, to strengthen the construction of the party play very important role. Along with the development of the situation, which many provisions have been unable to fully meet the comprehensive strictly administering the practice needs. One is Ji law, more than half of the provisions and cr
18、iminal law and other countries laws and regulations Repetition; two is the political discipline regulations is not prominent, not specific, for violation of the party constitution, damage the authority of Party Constitution of misconduct lack necessary and serious responsibility to pursue; third is
19、the main discipline for the leading cadres, does not cover all Party members. Based on the above situation, need to and the two is likely to be more relevant regulations first amendment. By revising, really put the authority of Party discipline, the seriousness in the party tree and call up the majo
20、rity of Party members and cadres of the party constitution of party compasses party consciousness. (II) two party regulations revision process the Central Committee of the Communist Party of China attaches great importance to two regulations revision . Xi Jinping, general books recorded in the Fifth
21、 Plenary Session of the eighth session of the Central Commission for Discipline Inspection, on the revised regulations made clear instructions. According to the central deployment, the Central Commission for Discipline Inspection from 2014 under six months begin study two regulations revision. The S
22、tanding Committee of the Central Commission for Discipline Inspection 4 review revised. Comrade Wang Qishan 14 times held a special meeting to study two regulations revision, amendment clarifies the direction, major issues of principle, path and target, respectively held a forum will listen to part
23、of the province (area) secretary of the Party committee, Secretary of the Discipline Inspection Commission, part of the central ministries and state organs Department The first party committee is mainly responsible for people, views of experts and scholars and grassroots party organizations and Part
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- pn 基本 电工仪表 使用 测量误差 计算
链接地址:https://www.31doc.com/p-2130867.html