电工基础(劳动版)第二章

1、电阻串联电路的特点电阻串联电路的特点 nnRURURU2211Ua = IaRa = 5010610103 = 0.5 Vk19010505 . 0106aaaXXIUUIURnEE 串nrR 串nIIII21nRRRR111121nnRIRIRIIR2211EE并nrr 并12121251251251253125312534AB125342244 42442244 4244RRRRRRRRRRRRRRRR 311266VUUU3316120.5URI33 16 0.53WPU I421257VUUU4427 17URI P4 = U4I2 = 7 1 = 7WUAB = UAD UBC =

2、UDC R1I1 = RxI2 R2I1 = RI2R1R = R2Rx重量变化电阻变化电压变化 电阻应变片放大电路数字显示电 桥I进 = I出 I1+ I2= I3+ I4 + I5I1+ I2 -I3 - I4- I5 = 0 I = 0I1I2 + I3 I4 = 02（3）+（2）I4 = 0I4 = 3 A 1230III30I 12II4530III45II30I IA = IAB-ICAIB = IBC-IABIC = ICA-IBCIAIBIC = 0或 I = 0U = 0电源电动势之和 = 电路电压降之和 攀登总高度 = 下降总高度UAB + UBC + UCD + UDA

3、 = 0E1I1R1 E2I2R2 = 0E1 + E2 = I1R1 + I2R2E = IRU = UAB + I2R2 - I1R1 = 0 I1 + I2 = I3E1 = I1R1 + I3R3E2 = I2R2 + I3 R3 I2= I3 I1 2I1 + 5I3 = 17 I2 + 5I3 = 17I1 = 1A I2 = 2A I3 = 3AI(R1 + R2 + R3) = E1 - E2121231861A246EEIRRRI = I-I= 1.5 - 0.5 = 1A1123181.5A246EIRRR 212360.5A246EIRRR 112312332123231

4、231810A1 41144108A141102A14EIR RRRRRIIRRRIIRR 2213213312131321395A1 4114454A14151A14EIR RRRRRIIRRRIIRRI1 = I1- I1=10-4=6AI2 = I2-I2=5-8=-3AI3 = I3+I3=2+1=3AS124A 3EIr内阻不变S2 816V EI r 内阻不变IS1 = = = 18A IS2 = = = 9A11ER18122ER91IS = IS1 +IS2 = 27A R = R1/R2 = 0.53S30.52740.53ARIIRRs1s2s12123111680.41611116104VUUIRRURRRs111s22233642A1842A640.4A10UUIRUUIRUIR E = ISR = 270.5 = 13.5VR = 0.53313.53A0.54EIRRAB112313123412.512.5105102.55207.5VUI RI REERRRRRR 1234AB123410 2.55 20102.55206R RR RRRRRR 0557.56690.1AEIrR（R+r）2 = （Rr）2+4Rr2222()EREPI RRRrRr2222()()44REEPRrRr