关键词: 静电场, 环路定理, 非抵消法证明

Abstract: The cycle theorem in electrostatic field is an important theorem in physics. The sole method to deduce itin all text books is that of offset. Two other methods than offset will be given in the present paper, which are more simple and skillful. Since this theorem is quite fundamental, it is quite attractive to physics teaching to seek for different proofs.

Key words: electrostatic field, cycle theorem, non-offset