半导体二极管电子教案

半导体二极管电子教案 第一章 半导体二极管 内容简介 本章首先介绍半导体的导电性能和特点，进而从原子结构给与解释。先讨论PN结的形成和PN结的特性，然后介绍半导体二极管特性曲线和主要参数。 分析 定性数据统计分析pdf销售业绩分析模板建筑结构震害分析销售进度分析表京东商城竞争战略分析 这些管子组成的几种简单的应用电路，最后列出常用二极管参数及技能训练项目。 知识教学目标 1.了解半导体基础知识，掌握PN结的单向导电特性; 2.熟悉二极管的基本结构、伏安特性和主要参数; 3.掌握二极管电路的分析 方法 快递客服问题件处理详细方法山木方法pdf计算方法pdf华与华方法下载八字理论方法下载 ; 4.了解特殊二极管及其应用。 技能教学目标 能够识别和检测二极管，会测定二极管简单应用电路参数。 本章重点 1.要求掌握器件外特性，以便能正确使用和合理选择这些器件。如:半导体二极管:伏安特性，主要参数，单向导电性。 2.二极管电路的分析与应用。 本章难点 1.半导体二极管的伏安特性，主要参数，单向导电性。 2.二极管电路分析方法。 课时 4课时 题 快递公司问题件快递公司问题件货款处理关于圆的周长面积重点题型关于解方程组的题及答案关于南海问题 目:半导体、PN结 教学目标:了解本征半导体，杂质半导体的区别，从而得出半导体特性。记住半导体PN结的特性。 教学重点:1、半导体特性; 2、半导体PN结的特性; 教学难点:1、半导体单向导电性。 2、半导体PN结分别加正反向电压导通与截止的特性。 教学方法:讲授 教具:色粉笔 新课导入:电子技术基础是我们这学期新开的一门专业课，它包含各个基本小型电路的介绍及使用分析，这次课我们来学习一种材质:半导体。为以后的电路分析打下基础。 新授: 从导电性能上看，通常可将物质为三大类:导体: 电阻率 ，缘体:电阻率 ， 半导体:电阻率ρ介于前两者之间。目前制造半导体器件材料用得最多的有: 单一元素的半导体——硅(Si)和锗(Ge); 化合物半导体 —— 砷化镓(GaAs)。 an end to volunteer to do illegal things. Comrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable security environment, the economic environment of fair competition, standardized and orderly legal environment, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the county public security organs peace volunteers construction and deepen. The city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the public security team building higher expectations and requirements, we show that there are many does not reach the designated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing 图1.1.1 半导体示例 1.1.1 本征半导体 了解: 纯净的半导体称为本征半导体。用于制造半导体器件的纯硅和锗都是四价元素，其最外层原子轨道上有四个电子(称为价电子)。在单晶结构中，由于原子排列的有序性，价电子为相邻的原子所共有，形成图1.1.2所示的共价健结构，图中+4代表四价元素原子核和内层电子所具有的净电荷。共价键中的一些价电子由于热运动获得一些能量，从而摆脱共价键的约束成为自由电子，同时在共价键上留下空位，我们称这些空位为空穴，它带正电。在外电场作用下，自由电子产生定向移动，形成电子电流;同时价电子也按一定的方向一次填补空穴，从而使空穴产生定向移动，形成空穴电流。 因此，半导体中有自由电子和空穴两种载流参与导电，分别形成电子电流和空穴电流，这一点与金属导体的导电机理不同。 1.1.2 杂质半导体 在本征半导体中掺入某些微量的杂质，就会使半导体的导电性能发生显著变化。其原因是掺杂半导体的某种载流子浓度大大增加。 一、 N型半导体 若在四价的硅或锗的晶体中掺入少量的五价元素(如磷、锑、砷等)，则晶体点阵中的某些半导体原子被杂质取代，磷原子的最外层有五个价电子，其中四个与相邻的半导体原 子形成共价键，必定多出一个电 an end to volunteer to do illegal things. unty public security organs peace volunteers construction and deepen.rious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the con, glong environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opiniod stable security environment, the economic environment of fair competition, standardized and orderly legal environment, liviComrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability an every n is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we dohe city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfactioyear tweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this nt years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sThe city people a sense of security and satisfaction in rece, responsibility, closely combined with the area, the actual unit, carefully and find out the existingion place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisisposit public security team building higher expectations and requirements, we show that there are many does not reach the designatedthing meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the 2 子，这个电子几乎不受束缚，很容易被激发而成为自由电子，这样，在该半导体中就存在大量的自由电子载流子，空穴是少数载流子，这种半导体就是N型半导体 图1.1.3 N型半导体结构 二、 P型半导体 若在四价的硅或锗的晶体中少量的三价元素，如硼，晶体点阵中的某些半导体原子被杂质取代，硼原子的最外层有三个价电子，与相邻的半导体原子形成共价键时，产生一个空穴。这个空穴可能吸引束缚电子来填补，使得硼原子成为不能移动的带负电的离子,因而在该半导体中就存在大量的空穴载流子,当然,其中还有少数由于本征激发而产生的自由电子，如图1.1.4所示。 需要指出的是,无论是N型还是P型半导体,都是呈电中性的。 *综上所述，半导体特性: *1、半导体的导电能力介于导体与绝缘体之间。 2、在一定温度下，本征半导体因本征激发而产生自由 电子和空穴对，故其有一定的导电能力。 *3、本征半导体的导电能力主要由温度决定;杂质半导体的导电能力主要由所掺杂质的浓度决定。 4、P型半导体中空穴是多子，自由电子是少子。N型半导体中自由电子是多子，空穴是少子。 *5、半导体的导电能力与温度、光强、杂质浓度和材料性质有关。 1.1.3 PN结 一、PN 结的形成 在同一片半导体基片上，分别制造P 型半导体和N 型半导体，经过载流子的扩散，在它们的交界面处就形成了PN 结。 PN结是多数载流子的扩散运动和少数载流子的漂移运动相较量,最终达到动态平衡的必然结果，相当于两个区之间没有电荷运动，空间电荷区的厚度固定不变。 二、PN结的单向导电性 er to do illegal things.an end to volunte the county public security organs peace volunteers construction and deepen. d, toopinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahea t, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, publicrity environment, the economic environment of fair competition, standardized and orderly legal environmenComrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable secu e achievement, condensed the majority of police efforThe city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind thcrisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing nse ofignated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sey, the public security team building higher expectations and requirements, we show that there are many does not reach the desecurite we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social ssfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwisd satif this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security ant and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half o3 1、PN结的偏置 PN结加上正向电压(正向偏置)的意思都是:P区加正、N区加负电压。 PN结加上反向电压(反向偏置)的意思都是: P区加负、N区加正电压。 2、PN结正偏 如上图1.1.6所示,当PN结正偏时，外加电源形成的电场加强了载流子的扩散运动，削弱了内电场，耗尽层变薄，因而多子的扩散运动形成了较大的扩散电流。用流程图表述如下:PN结正偏外电场削弱内电场 耗尽层变薄 扩散运动漂移运动多子扩散运动形成正向电流 。 3、PN结的反偏 在PN结加反向偏置时,如图1.1.7所示，外加电源形成的外电场加强了内电场，多子的扩散运动受到 阻碍，耗尽层变厚;少子的漂移运动加强，形成较小的漂移电流。其过程表述如下: PN结反偏 外电场加强内电场 耗尽层变厚扩散运动漂移运动 少子漂移运动形成反向电流 。 综上所述: 1)PN结加正向电压时，具有较大的正向扩散电流，呈现低电阻， PN结导通; 2)PN结加反向电压时，具有很小的反向漂移电流，呈现高电阻， PN结截止。 课后总结:这次课我们认识了半导体材料。对于半导体的特性，PN结的特性进行对比记忆，由大家课下熟悉完成记忆。 作业:练习册1.1 板书 设计 领导形象设计圆作业设计ao工艺污水处理厂设计附属工程施工组织设计清扫机器人结构设计 : 一、半导体 1、 本征半导体 2、 杂质半导体: 二、PN结 an end to volunteer to do illegal things. unty public security organs peace volunteers construction and deepen.rious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the con, glong environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opiniod stable security environment, the economic environment of fair competition, standardized and orderly legal environment, liviComrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability an every n is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we dohe city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfactioyear tweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this nt years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sThe city people a sense of security and satisfaction in rece, responsibility, closely combined with the area, the actual unit, carefully and find out the existingion place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisisposit public security team building higher expectations and requirements, we show that there are many does not reach the designatedthing meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the 4 题目:1.2 二极管的特性及主要参数 教学目标:了解二极管的特性，分析使用二极管时的主要参数-伏安特性。 教学重点:二极管结构分析，伏安特性的分析; 教学难点:1、伏安特性分析。 2、几个参数的记忆及区分。 教学方法:讲授 教具:色粉笔 新课导入:上次课我们认识了半导体器件中常用的器件“二极管”，在使用过程中不仅要了解它的参数也是不行的，这次我们继续学习它的特性及参数要求。 新授: 1.2.1 半导体二极管的结构和符号 形成PN结的P型半导体和N型半导体上，分别引出两根金属引线，并用管壳封装，就制成二极管。其中从P区引出的线为正极，从N区引出的线为负极。二极管的结构外形及在电路中的文字符号如图1.2.1所示。在图1.2.1(b)所示电路符号中，箭头指向为正向导通电流方向，二极管常见的封装形式如图1.2.2所示。 1.2.2 二极管的伏—安特性 半导体二极管的核心是PN结，它的特性就是PN结的单向导电特性。常利用伏一安特性曲线来形象地描述二极管的单向导电性。所谓伏安特性，是指二极管两端电压和流过二极管电流的关系，可用电路图来测量。若以电压为横坐标，电流为纵坐标，用作图法把电压、电流的对应值用平滑曲线连接起来，就构 er to do illegal things.an end to volunte the county public security organs peace volunteers construction and deepen. d, toopinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahea t, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, publicrity environment, the economic environment of fair competition, standardized and orderly legal environmenComrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable secu y, the public security team building higher expectations and requirements, we show that there are many does not reach the desecurite we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social ssfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwisd satif this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security ant and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half oe achievement, condensed the majority of police efforThe city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind thcrisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing nse ofignated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the se5 成二极管的伏—安特性曲线，如图1.2.3所示(图中虚线为锗管的伏—安特性，实线为硅管的伏—安特性)，下面以二极管的伏—安特性曲线加以说明。 一、正向特性 当二极管两端加正向电压时，就产生正向电流，正向电压较小时，正向电流极小(几乎为零)，这一部分称为死区，相应的A(A′)点的电压命名为死区电压。 二极管正向导通时，要特别注意它的正向电流不能超过最大值，否则将烧坏PN结。 二、反向特性 当二极管两端加上反向电压时，在开始很大范围内，二极管相当于非常大的电阻，反向电流很小，且不随反向电压而变化。此时的电流称之为反向饱和电流，如图1.2.3中0C(或O′C′)段所示。 三、反向击穿特性 二极管反向电压加到定数值时，反向电流急剧增大，这种现象称为反向击穿。此时的电压称为反向击穿电压用表示，如图1.2.3中CD(或C′D′)段所示。 四、死区电压:锗——0.2V 硅——0.5V 五、导通电压降:锗——0.3V 硅——0.7V 1.2.3 半导体二极管的主要参数和分类 基本参数: 1(最大整流电流 an end to volunteer to do illegal things. unty public security organs peace volunteers construction and deepen.rious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the con, glong environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opiniod stable security environment, the economic environment of fair competition, standardized and orderly legal environment, liviComrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability an , responsibility, closely combined with the area, the actual unit, carefully and find out the existingion place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisisposit public security team building higher expectations and requirements, we show that there are many does not reach the designatedthing meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the every n is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we dohe city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfactioyear tweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this nt years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sThe city people a sense of security and satisfaction in rece6 最大整流电流是指二极管长期工作时，允许通过的最大平均电流使用正向平均电流能超过此值，否则二极管会击穿。 2(最大反向工作电压 最大反向工作电压是指二极管正常工作时，所承受的最高反向电压(峰值)。通常手册上给出的最大反向工作电压是击穿电压的一半左右。 3(二极管的直流电阻 二极管的直流电阻指加在二极管两端的直流电压与流过二极管的直流电流的比值。二极管的正向电阻较小，约为几欧到几千欧;反向电阻很大，一般可达零点几兆欧以上。 4(最高工作频率 最高工作频率是指二极管正常工作时上、下限频率，它的大小与PN结的结电容有超过此值，二极管单向导电特性变差。 课后总结: 这次课的重点:1、二极管结构及其单向导电性 2、 死区电压:锗——0.2V 硅——0.5V 3、导通电压降:锗——0.3V 硅——0.7V 4、二极管反向电压加到定数值时，反向电流急剧增大，这种现象称为反向击穿 作业:练习册1.2填空1-5题 板书设计:一、半导体二极管的结构和符号 二、二极管的伏—安特性 三、半导体二极管的主要参数和分类 er to do illegal things.an end to volunte the county public security organs peace volunteers construction and deepen. d, toopinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahea t, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, publicrity environment, the economic environment of fair competition, standardized and orderly legal environmenComrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable secu nse ofignated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sey, the public security team building higher expectations and requirements, we show that there are many does not reach the desecurite we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social ssfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwisd satif this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security ant and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half oe achievement, condensed the majority of police efforThe city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind thcrisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing7 题目:1.4特殊二极管、二极管的检测及应用 教学目标:1、稳压二极管、发光二级管及光电二极管的特点 2、学习二极管极性检测 3、学习二极管好坏的检测 教学重点:1、学习二极管极性检测 2、学习二极管好坏的检测 教学难点:1、二极管的检测 、二极管的应用 2 教学方法:讲授 教具:色粉笔 新课导入:二极管大家已经知道是什么电子器件，那么如果拿来一个二极管，如何知道它的正负极,二极管的好坏该怎样检测,这一系列使用前应该做的准备都是必须有的，现在我们就来学习他的检测方法～ 新授: 1.4.1 稳压二极管 稳压电路利用稳压二极管在反向击穿特性来实现稳压。下面简要介绍稳压二极管基本知识。 一、稳压二极管的工作特性 稳压二极管简称稳压管，它的伏一安特性曲线和在电路中的符号如图1.4.1所示。稳压管和普通二极管正向特性相同，不同的是反向击穿电压较低，且击穿特性陡峭，这说明反向电流在较大范围内变化时，击穿电压基本不变，稳压管正是利用反向击穿特性来实现稳压的，此时击穿电压称为稳定工作电压，用 UZ表示。 二、稳压管的主要参数 稳定电压U1. Z 稳定电压U 即反向击穿电压。由于击穿电压与制造 工艺 钢结构制作工艺流程车尿素生产工艺流程自动玻璃钢生产工艺2工艺纪律检查制度q345焊接工艺规程 、环境温度和工作电流有关，手册中只能给出Z 某一型号的稳压范围。 2.稳定电流I Z 稳定电流I 是指稳压管工作至稳定状态时流过的电流。当稳压管稳定电流小于最小稳定电流 时，没有Z 稳定作用;大于最大稳定电流 时，管子因过流而损坏。稳压管由于受热而击穿。 an end to volunteer to do illegal things. unty public security organs peace volunteers construction and deepen.rious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the con, glong environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opiniod stable security environment, the economic environment of fair competition, standardized and orderly legal environment, liviComrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability an , responsibility, closely combined with the area, the actual unit, carefully and find out the existingion place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisisposit public security team building higher expectations and requirements, we show that there are many does not reach the designatedthing meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the every n is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we dohe city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfactioyear tweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this nt years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sThe city people a sense of security and satisfaction in rece8 1.4.2 发光二极管与光电二极管 一、发光二极管 发光二极管是一种把电能变成光能的器件，由磷化镓、砷化镓等半导体材料制成，电路符号见图1.4.3,当给发光二极管加上偏压，有一定的电流流过时二极管就会发光，这是由于PN结的电子和空穴直接复合放出能量的结果。 ? 颜色:发光二极管的种类按发光的颜色可分为:红色、蓝色、黄色、绿色和无色 ? 正负极:管脚引线较长者为正极，较短者为负极。 ? 不同颜色发光二级管工作电压: 发光二极管工作时导通电压比普通二极管大，其工作电压随材料不同而不同，一般为1.7v, 2.4v。 普通绿、红、黄二极管工作电压约为2v， 白色发光二极管电压通常高于2.4v; 蓝色发光二极管工作电压一般高于3.3v。 发光二极管的工作电流一般为2mA,25mA。 发光二极管广泛应用于各种电子仪器仪表、计算机、 电视机的电源指示和信号指示，还可以做成七段译码显示器等。 二、光电二极管 光电二极管又叫光敏二极管，外形如图1.4.5。光电二极管也是由一个PN 结构成，但是它的PN面积较大，通过管壳上的一个玻璃来接收入射光。它是利用PN在施加反向电压时，在光线照射下反向电阻由大变小来工作的，其工作电路如1.4.4。光电二极管可用于光测量、光电控制等方面，如遥控接收器、光纤通讯、激光头中都用到光电二极管。 er to do illegal things.an end to volunte the county public security organs peace volunteers construction and deepen. d, toopinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahea t, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, publicrity environment, the economic environment of fair competition, standardized and orderly legal environmenComrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable secu nse ofignated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sey, the public security team building higher expectations and requirements, we show that there are many does not reach the desecurite we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social ssfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwisd satif this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security ant and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half oe achievement, condensed the majority of police efforThe city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind thcrisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing 9 1.5 二极管的检测与应用 1、二极管的识别 二极管正负极、规格、功能和制造材料一般可以通过管壳上的标志和查阅手册(本章内容后附有实用资料)来判断，如IN4001通过壳上的标志可判断正负极，查阅手册可知它是整流管，参数是1A/50V;2CW15查阅手册可知它是N型硅材料稳压管。如果管壳上无符号或标志不清，就需要用万用表来检测。 2、二极管的检测 二极管的检测主要是判断其正负极和质量好坏。 基本方法: (1) 选档位 将万用表量程调至 R×100Ω 或 R×1KΩ档(一般不用 R×1Ω档，因其电流较大，而 R×10K档电压过高管子易击穿) (2) 测电阻 将两表笔分别接触二极管两个电极，测得一个电阻值，交换一次电极再测一次，从而得到两个电阻值。 正向电阻,5KΩ 反向电阻,500KΩ， an end to volunteer to do illegal things. unty public security organs peace volunteers construction and deepen.rious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the con, glong environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opiniod stable security environment, the economic environment of fair competition, standardized and orderly legal environment, liviComrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability an , responsibility, closely combined with the area, the actual unit, carefully and find out the existingion place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisisposit public security team building higher expectations and requirements, we show that there are many does not reach the designatedthing meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the every n is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we dohe city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfactioyear tweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this nt years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sThe city people a sense of security and satisfaction in rece10 如图1.5.1所示。 (3)问题分析 性能好的二极管，一般反向电阻比正向电阻大几百倍。 ? 如两次测得的正、反向电阻很小或等于零，则说明管子内部已击穿或短路; ? 如果正、反向电阻均很大或接近无穷大，说明管子内部已开路; ? 如果电阻值相差不大，说明管子性能变差; ? 在上述三种情况的二极管均不能使用。 作业:练习册1.2填空1-5题 课后总结: 这次课的重点:1、各种特别二极管的特点简介 2、二极管的极性及性能好坏的检测 板书设计:1、各种特别二极管的特点简介 2、二极管的极性及性能好坏的检测 er to do illegal things.an end to volunte the county public security organs peace volunteers construction and deepen. d, toopinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahea t, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, publicrity environment, the economic environment of fair competition, standardized and orderly legal environmenComrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable secu sfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwisd satif this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security ant and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half oe achievement, condensed the majority of police efforThe city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind thcrisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing nse ofignated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sey, the public security team building higher expectations and requirements, we show that there are many does not reach the desecurite we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social s11