全波（或半波）整流器電輸出每秒有120（或60）次為零。波形分析法即利用整流器此一快速斷電器電象，即可不用將陰極防蝕電源斷電，而取得極化電位。

The current output of a full-wave (or half-wave) rectifier goes to zero 120(or 60) times every second. Thereby, the standard rectifier itself acts as a fast interruption circuit. The waveform analysis method is based on this phenomenon. AD/DA card and microprocessor of comupter were used to read potential waveform data and a computer software was used to analyze waveform data. The pipe-to-soil potential and the polarization potential can be fastly obtained by above package.