第二节焊接技能的讲解与常用仪器的 使用 主讲人：*Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.万用表Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.基本功能1、直流电压测量 2、交流电压测量 3、直流电流测量 4、交流电流测量 5、电容测量 6、电阻测量Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.v一、电压的测量1、直流电压的测量。首先将黑表笔插进“com” 孔，红表笔插进“V ”。把旋钮选到比估计值大的 量程 （注意：表盘上的数值均为最大量程，“V” 表示直流电压档），接着把表笔接电源或电池两端 ；保持接触稳定。数值可以直接从显示屏上读取， 若显示为“1.”，则表明量程太小，那么就要加大量程 后再测量工业电器。 如果在数值左边出现“-”，则表 明表笔极性与实际电源极性相反，此时红表笔接的 是负极。v 2、交流电压的测量。表笔插孔与直流电压的测 量一样，不过应该将旋钮打到交流档“V”处所需的 量程即可。交流电压无正负之分，测量方法跟前面 相同。 无论测交流还是直流电压，都要注意人身安 全，不要随便用手触摸表笔的金属部分。 Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.v二、电流的测量1、直流电流的测量。先将黑表笔插入“COM” 孔。若测量大于200mA的电流，则要将红表笔插入 “10A”插孔并将旋钮打到直流 “10A”档；若测量小于 200mA的电流，则将红表笔插入 “200mA”插孔，将 旋钮打到直流200mA以内的合适量程。调整好后， 就可以测量了。将 万用表串进电路中，保持稳定， 即可读数。若显示为“1.”，那么就要加大量程；如果 在数值左边出现“-”，则表明电流从黑表笔流进万用 表。2、交流电流的测量。测量方法与1相同，不过 档位应该打到交流档位。 Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.三、电阻的测量将表笔插进“COM”和“V”孔中，把旋钮 打旋到“”中所需的量程，用表笔接在电阻两 端金属部位，测量中可以用手接触电阻，但 不要把手同时接触电阻两端，这样会影响测 量精确度的人体是电阻很大但是有限大 的导体。读数时，要保持表笔和电阻有良好 的接触；注意单位：在“200” 档时单位是“” ，在“2K”到“200K“档时单位为 “K ”，“2M”以 上的单位是“M”。 Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.二极管档 原理：一个电源串联蜂鸣器,然后两端就是 触笔了,如果二极管是导电那一向,线路接通, 蜂鸣器就会叫了,反过来,蜂鸣器就叫不出来了 一般会带有测电路通不通的功能，就是说 当被测电路中的电阻小于10欧姆的时候就会 发出报警声 。二极管档是用来测二极管好坏 的，二极管的性质就是单向导电，测量值表 示二极管的正向电压值，单位为V。 注意：万用表二极管档是不允许通电的情 况下测试器件的 。Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.三极管最基本的作用是放大作用 Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.v按材料不同分锗管和硅管，按半导体基片材 料的不同分为PNP型和NPN型，有三个极， 分别为B极（基极）、C极（集电极）、E极 （发射极），三极管在电路中的符号是“VT” 或“Q”或“V”。晶体管是电流控制元件。 v主要参数：放大倍数、截止频率、集电极最 大电流、集电极最大功耗等v常用PNP管：8550、9012、9015v常用NPN管：8050、9018、9016、9014、 9013、9011Evaluation only.Evaluation only. Created with Aspo