Investigation of the Electromagnetic Interference Effect on a Conduction Wire in a Schmitt Trigger Circuit

Abstract

本研究以實際設計的施密特觸發器的電子電路，得其二個起動轉態電壓V1 與V2，再從電磁干擾（EMI）理論及實際量測結果去証實電磁干擾的影響函數參數，進而量化其干擾量。此量化結果顯示EMI 的干擾量與干擾頻率及干擾振幅有關，較高的干擾頻率及干擾振幅有較大的輸出電壓Vrms-out，此與本文所推導的EMI 理論相吻合。

In this study of the Schmitt trigger, the researcher initially designed an electrical circuit and then determined two threshold transfer voltages, V1 and V2. From experimental results and electromagnetic interference [EMI] theory, it was hypothesized and verified that the degree of influence of EMI is a function of R1, R2, Rc1, Re, B1, B2, Ie1, Ie2 and of the amount of radiated power. Furthermore, the degree of influence of the EMI was quantified. The quantified data reveal that the influence of the EMI is related to the interference frequency and interference amplitude. Specifically, higher frequencies and greater amplitudes of interference tend to have a greater influence upon the output Vrms-out. The present results are clearly in agreement with those predicted by EMI theory.