单项选择题
The characteristic of an ideal diode are those of a switch that can conduct current（）.
A.in both directions B.in one direction only C.in both directions but in only one direction at a time D.depends on the circuit it is used in
单项选择题 Which of the following is not a commonly used semiconductor material’？（）
问答题 试分析图电路的输出电压可调节的范围。
问答题 试推导图电路中输出电流IO的表达式。A为理想集成运算放大器，且可以正常工作；三端集成稳压器CW7824的3、2端间的电压用UREF表示。
