Using the characteristics of high self inductance coefficient of fluorescent lamp inductor ballasts and ordinary small self inductance coils, a teaching experience experiment is designed. Based on the experimental phenomena, a more in-depth study is conducted on the self inductance problem, and expressions for the self induced electromotive force and self induced current of the experimental circuit during the electrification and power-off processes in a linear model are provided.  We analyze the reasons for the incomplete agreement between the results of linear theory and experimental phenomena, and correcte the erroneous understanding of self induced current and self induced electromotive force in relevant literature.