集电极电源是通过（）给晶体管的集电结加以反向偏压并对放大器提供电源的。
参考答案：集电极负载电阻
For more than 20 years, we've been supporting educational programs that _____ from kindergartens to
colleges. [ ]
A. spread
B. move
C. shift
D. range
清代学者的实事求是的精神表现在哪里？
