Experimental circuit demonstrator and the student test circuit board are supplied to junior high schools in demonstrating and separating for 9 basic electronic experiments altogether. All parts of the apparatus were welded in each transparent plastics box, and these boxes can be expediently inserted or pulled out of the scale board; On the scale board, the nine eyelets combined with the “田” are connected, they can be used as a node when we do experiments. Electric circuits of experiments can be conveniently and reliably connected.