《电容器的电容》一节是《电场》这一章的重点与难点.其难点来自两个方面:一是知识点(电容概念难理解);二是实验(没有现成的教学仪 The section “Capacitors of Capacitors” is the focus and difficulty of the chapter “Electric Field.” The difficulties come from two aspects: one is knowledge point (the concept of capacitance is difficult to understand); the other is experiment (no existing teaching instrument