RLC circuit is an important part of college physics and circuit analysis, and it is also a basic unit of electronic instruments and communication equipment, When the RLC circuit is working, the voltage at both ends of the capacitor will be overcharged beyond the supply voltage. However, existing textbooks lack necessary theoretical explanations for this phenomenon, In fact, the phenomenon of overcharging contains rich physical images. On the basis of experimental observation and analysis of the physical quantity dependence of various components in the transient process, this article conducts quantitative research from both micro and macro perspectives, explaining that the overcharging phenomenon is caused by the presence of inductance, which affects the current change mode. When the capacitor voltage reaches thepower supply voltage, the current does not reach zero, while the charging process continues,leading to the overcharging phenomenon of the capacitor voltage. The results of this paper arehelpful for students to understand the transient process of RLC circuit more deeply.

When the current passes through the thermocouple circuit, heat is released at one junction and absorbed at another junction. This effect is called Peltier effect, which is an important knowledge point of nonequilibrium thermodynamics. In this paper, a comprehensive experimental device for thermal process research based on Peltier effect is designed and manufactured. The effect of working current on the temperature difference between the cold and hot ends of semiconductor refrigeration sheets is experimentally studied by using the device. The result is consistent with the heat transfer model considering heat conduction, Joule heat effect and Peltier effect. The variation of temperature with time in the cold end and insulation box is studied experimentally. Especially, it is important to use the large amount of heat generated by Peltier effect in the refrigeration process to study the Fourier heat conduction law simultaneously. The related experimental items of the experimental device are applied to the college physics experiment course, and the teaching effect is good.