RLC串联谐振回路中,R=13Ω,L=0.25mH,C=100pF,输入电压U=0.1mV。则谐振时电阻上的电压有效值为( )。
A campus emergency ______ occur at any time of the day or night, weekend, or holiday, with little or no warning.
免费的网站请分享给朋友吧