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小明和小红非常好动脑筋,对学习的知识经常会多问几个为什么.在学了《电流的强弱》以后,他们经过思考,带着对电流表使用的许多疑问一起去找老师. 小明:老师,您在电流表的连接中反复强调.电流表的接线柱一定不能接错,必须使电流从“+”接线柱流进去,从“-”接线柱流出来.为什么? 老师:这有两个原因,一是电路中电流是有方向的;二是电流表内部构造和工作原理都与电流的方向有关.电流表制成以后,电流通过电流
Xiao Ming and Xiao Hong are very good brains. They often ask a few questions about why they learn. After learning about the strength of the current, they went through the thoughts and went to the teacher with many questions about the use of the ammeter. Xiao Ming: Teacher, you repeatedly stressed in the connection of the ammeter. The terminal of the ammeter must not be connected wrongly. The current must flow from the “+” terminal and flow from the “-” terminal. Why? Teacher: There are two reasons for this. First, the current in the circuit is directional; second, the internal structure and working principle of the ammeter are related to the direction of the current. After the current meter is made, the current passes through the current.