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电功实验是初中物理第二册第九章的第一个演示实验。做好这一实验,既能帮助学生形成电功的概念,理解电功与机械功之间的联系,还能对影响电功大小的因素加深印象,因此做好这一实验,是学好这一章的关键。现将改进的实验装置介绍如下。一、实验装置选用市售的玩具直流电动机(3伏、0.8安),因为转速太快,故在转轴上装配涡轮涡杆,达到减速的目的。为了减少实验过程中的观察内容和简化实验装置,而直接用一节干电池或二节干电池以示电压高低,这样就减少了电压表和滑线变阻器。整个装置如图所示,时间用电钟(挂在黑板上)读出。
The electrical work experiment is the first demonstration experiment in the ninth chapter of the second book of junior middle school physics. Doing this experiment can not only help students form the concept of electric power, understand the connection between electric power and mechanical work, but also deepen the impression on the factors that affect the size of electric power. Therefore, to do this experiment is to learn this well. The key to the chapter. The improved experimental setup is now described below. First, the experimental device uses a commercially available toy DC motor (3 V, 0.8 A), because the speed is too fast, so the turbine worm shaft assembly on the shaft, to achieve the purpose of deceleration. In order to reduce the observation content during the experiment and simplify the experimental device, a dry cell or two dry cells are directly used to indicate the voltage level, thus reducing the voltage meter and the sled varistor. The entire device is shown in the figure and the time is read with the electric clock (hanging on the blackboard).