熔断器保护的选择性要求后级的被保护对象发生短路时,()。A、前级应先熔断;B、后级应先熔断;C、前后级应同时熔断;D、前后任一级先熔断均可。...
Wednesday, November 22, 2023
Friday, September 16, 2022
Monday, March 25, 2024
Friday, September 16, 2022
并联谐振又称为()谐振。A、电阻;B、电流;C、电压;D、电抗。...
Tuesday, April 16, 2024
Friday, September 16, 2022
Friday, September 16, 2022
Monday, February 12, 2024
Friday, September 16, 2022
振动试验属于()的一种。A、结构和机械试验;B、气候影响试验;C、绝缘性能试验;D、电源影响试验。...
Friday, November 25, 2022
负控终端的输入信号分三类:脉冲量、模拟量和开关量。脉冲量来自电流...
Friday, September 16, 2022
终端的电源部分主要作用是将220V交流电变换成机内各部件所需的直流电源。()...
Saturday, August 12, 2023
通电后,由于电磁铁的吸合动作而使低压自动空气断路器跳闸的电气装置,称为()脱扣器。A、过流;B、失压;C、分励;D、负压。...
Monday, February 6, 2023
计算题:现场工作人员检测到三相有功电能表1min发出了30个脉冲...
Friday, September 16, 2022
Sunday, February 26, 2023
Tuesday, September 13, 2022
用电压表测得的交流电压是()。A、最大值;B、有效值;C、平均值;D、瞬时值。...
Wednesday, November 22, 2023
在晶体管电路中,为了利用RC相移网络倒180°,至少要用()RC相移网络。A、一节;B、二节;C、三节;D、四节。...
Wednesday, April 3, 2024
Friday, November 3, 2023