Unit 4 Electro technics,电工学,Unit goals,electrician bag 电工包,Brainstorm 你所知道的电工工具,Do you know the names of electrician tools?,electrician tool 电工工具,insulating tape 绝缘胶带,wire(电线）,test pencil(测电笔）,Multimeter(万用表）,你知道哪些电路元器件符号？,对话操练,A: What does the symbol(符号）stand for(代表）? B: It stands for DC voltage source.,基本电路图 A Basic Electric Circuit,一个基本的电路图 这是一个基本的电路图。左边的电压源V驱使电流I在电路四周流动，把电能输送到电阻器R。电流从电阻器出发返回到电压源，完成一圈绕行。这种电路属于直流电路。,进户线,电表,总开关,电器,插座,导线,Speaking : Dialogue One,测试仪表 test instrument 万用表 multimeter 数字万用表 digital multimeter 导电测试 conductivity test,A:,B:,A:,B:,仿照对话一，对测试仪表进行问答：,这是哪种仪器？,这叫/这是万用表。,这种仪器能做什么？,它可以测量直流，交流电压，电阻和做导电测试，等等。,最大输入电压 maximum input voltage 功能开关 function switch 测试头 test leads 电路 circuit,Speaking : Dialogue Two,How to measure AC Voltage 如何测量交流电压,Practice :make a dialogue .根据对话二和下面所给句子，说明直流电压的测量步骤。,How to measure DC voltage? 如何测量直流电压 Step 1 set the function switch to ACV. 第一步： 将功能开关至于ACV Step 2 connect the test leads to the circuit to be measured. 第二步 将测试表接在被测电路上 Step 3 read the display. 第三步 读出数值,Reading : Top 10 Electric Safety Rules 10条重要的安全用电规则,plug 插头 plug into把插入到 Safety cap 电源安全盖 electrical outlet 电源插座 electric cord 电源线 tuck away 收拢，隐藏 grow-up 成人 look up and look out 四处张望 power line 电源线 substation 变电站 watch out 注意，留意 electrical stuff 电气材料 keep away from 让远离 fly a kite 放风筝,Reading : Top 10 Electric Safety Rules,12. 根据课文内容判断正误。 1. F It is safe to plug a bunch of wires into one outlet or extension cord. 2. F It is the right way to pull an electrical cord straight from the wall. 3. T It is the right way to make sure all electric cords are tucked away neatly. 4. T It is the right way to keep electric stuff far away form water to avoid the electrical accidents. 5. F It is safe to fly kites near power lines,13.小组讨论： 区分下列哪些操作是安全的，哪些是不安全的，并分类。,Plug a bunch of wires into one outlet. Cover outlets. Pull on a cord. Tuck away all electric cords neatly. Use electrical appliances near water. Screw lamp cap should be used and installed security cover. Disconnect rice cookers , induction cookers and other mobile appliances from the plugs. Unplug or plug household appliances frequently.,15. 用所给词汇填空。,electrician AC circuit damage test pencil Connect trip and fall electrician accident watch out,同学们，第四单元学完了，你对自己的所得还满意吗？让我们再接再厉，期待下一单元的知识吧！,