The electric field generated by a changing magnetic field is not a conservative field. In non-conservative fields, voltage is not well-defined, and using Kirchhoff's voltage law may not accurately reveal the physical processes in a circuit. However, using Faraday's law of electromagnetic induction can avoid the problem of defining voltage in non-conservative fields and offers an advantage in dealing with circuits in changing magnetic fields. By calculating the line integral of the electric field and applying Faraday's law of electromagnetic induction, one can not only obtain correct results but also present a clear physical picture of the circuit's interior, clarifying some widespread misconceptions. If the teaching of electromagnetic induction laws includes such applications, it can deepen students' understanding of circuits and the fundamental laws of electromagnetism.

The current impedance spectroscopy measurement techniques face difficulties in diagnosing solar cell faults due to issues such as cost, complexity, and accuracy. Therefore, a novel system was developed for precise broadband impedance spectrum measurement of solar cells, which was composed of an oscilloscope, a signal generator, and a sampling resistor. The results demonstrate concurrent accurate measurement of the impedance spectrum (50 Hz－0.1 MHz) and direct current voltametric characteristics. Comparative analysis with Keithley 2450 data yields a global relative error of approximately 6.70%, affirming the accuracy. Among excitation signals (sine, square, triangle, pulse waves), sine wave input yields the most accurate data, with a root mean square error of approximately 13.3016 and a global relative error of approximately 4.25% compared to theoretical data. Elevating reference resistance expands the half circle in the impedance spectrum. Proximity of reference resistance to that of the solar cell enhances the accuracy by mitigating line resistance influence. Measurement error is lower in high-frequency regions due to a higher signal-to-noise ratio.