Ideally, if the semiconductor diode is to behave like a closed switch in the ไบอัสตรง บริเวณ, the resistance of the diode should be 0 . In the reverse-bias region its resistance should be to represent the open-circuit equivalent. Such levels of resistance in the นำหน้า and reverse-bias บริเวณ result in the characteristics of Fig. 1.22 .