【单选题】
有一变压比为2的变压器,如在次级上接50的电阻,则变压器的输入阻抗为_______。___
A. 200
B. 25
C. 100
D. 12.5
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晶体三极管极性的结构有PNP型和_______。___
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用万用表测得二极管正、反向电阻都为无穷大,表明该二极管_______。___
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拆卸蓄电池,宜_______。___
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电风扇在额定电压下连续工作一小时,测量绝缘电阻不小于_______兆欧。___
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流体在管道中流动,通过阀门,孔板等设备时,由于局部阻力,使流体的压力_______,这种现象就称为节流现象。___
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防滑器速度传感器软管最小弯曲半径为_______mm。___
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