电工基础的题目:`````````````````````````````````````````````````````````````````````````````习题:在题图中,已知E=220v,R1=25Ω,R2=55Ω,R3=30Ω.求:(1)开关S打开时电路中的电流及电阻上的电压.(2)开关S合上后
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![电工基础的题目:`````````````````````````````````````````````````````````````````````````````习题:在题图中,已知E=220v,R1=25Ω,R2=55Ω,R3=30Ω.求:(1)开关S打开时电路中的电流及电阻上的电压.(2)开关S合上后](/uploads/image/z/6370197-69-7.jpg?t=%E7%94%B5%E5%B7%A5%E5%9F%BA%E7%A1%80%E7%9A%84%E9%A2%98%E7%9B%AE%EF%BC%9A%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%60%E4%B9%A0%E9%A2%98%3A%E5%9C%A8%E9%A2%98%E5%9B%BE%E4%B8%AD%2C%E5%B7%B2%E7%9F%A5E%3D220v%2CR1%3D25%CE%A9%2CR2%3D55%CE%A9%2CR3%3D30%CE%A9.%E6%B1%82%EF%BC%9A%EF%BC%881%EF%BC%89%E5%BC%80%E5%85%B3S%E6%89%93%E5%BC%80%E6%97%B6%E7%94%B5%E8%B7%AF%E4%B8%AD%E7%9A%84%E7%94%B5%E6%B5%81%E5%8F%8A%E7%94%B5%E9%98%BB%E4%B8%8A%E7%9A%84%E7%94%B5%E5%8E%8B.%EF%BC%882%EF%BC%89%E5%BC%80%E5%85%B3S%E5%90%88%E4%B8%8A%E5%90%8E)
电工基础的题目:`````````````````````````````````````````````````````````````````````````````习题:在题图中,已知E=220v,R1=25Ω,R2=55Ω,R3=30Ω.求:(1)开关S打开时电路中的电流及电阻上的电压.(2)开关S合上后
电工基础的题目:`````````````````````````````````````````````````````````````````````````````
习题:
在题图中,已知E=220v,R1=25Ω,R2=55Ω,R3=30Ω.求:
(1)开关S打开时电路中的电流及电阻上的电压.
(2)开关S合上后,各电阻上的电压是增大还是减小,为什么?
电工基础的题目:`````````````````````````````````````````````````````````````````````````````习题:在题图中,已知E=220v,R1=25Ω,R2=55Ω,R3=30Ω.求:(1)开关S打开时电路中的电流及电阻上的电压.(2)开关S合上后
开关S打开时,R1、R2、R3处于串联状态,因此:
I=U/(R1+R2+R3)=220/(25+55+30)=2(A)
U1=I*R1=2*25=50(V)
U2=I*R2=2*55=110(V)
U3=I*R3=2*30=60(V)
开关S合上后:
R2处于短路状态,只有R1、R3处于串联状态,因此:
I=U/(R1+R3)=220/(25+30)=4(A)
U1=I*R1=4*25=100(V) 增大
U2=0(V)
U3=I*R3=4*30=120(V) 增大
开关S打开时:
I=U/(R1+R2+R3)=220/(25+55+30)=2(A)
U1=I*R1=2*25=50(V)
U2=I*R2=2*55=110(V)
U3=I*R3=2*30=60(V)
开关S合上后:
R2短路
I=U/(R1+R3)=220/(25+30)=4(A)
U1=I*R1=4*25=100(V) 增大
U2=0(V)
U3=I*R3=4*30=120(V) 增大