串联型稳压电源正常工作的条件是 :其调整管必须工作于放大状态,即必须满足。
A. VI = VO + VCES
B. VI < VO + VCES
C. VI ≠ VO + VCES
D. VI > VO + VCES
查看答案
W7805输出电压 V,而W7912则输出电压V。
The cultivated land in the U.S. makes up ___ ____ of the total land, and people who are engaged in farming make up only 2.7% of the total population.
A. 21%
B. 31%
C. 41%
D. 51%
The Constitution of the United States provides that __ ____ shall be President of the Senate.
A. the Secretary of State
B. the Chief Justice
C. the President
D. the Vice President
The typical organizational pattern for elementary and secondary schools in the United States is that of ____ ___ .
A. classified schools
B. vocational schools
C. graded schools
D. public schools