The apparatus is for the use in middle school for studens in group to carry out esperinent on physics. Through the experiment the following objectives can be achieved: 1. The knowledge of the working principle of dynamo, that electrical energy can be transformed into mechanical energy. 2. By disassemblying and assemblyin the dynamo, to be familiar with main structure of the dynamo. 3. To train the students and acquire a certain degree of skill of doing experiment.