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標題:
好想知點計
發問:
欲使跨於4W電阻器的電壓為零時，則電流源IS的大小為多少 圖片參考：http://imgcld.yimg.com/8/n/HA07959059/o/701111070068013873398600.jpg 更新: 希望詳細解釋 更新 2: 答顥係 Vs=Is x 4(6+2)/(4+6+2)=2.671 Is ^ | | 唔明個R點做出來
最佳解答:
You have already got the answer, then what is your question? To the current source, the 4-ohm resistor is in parallel with the 6-ohm and 2-ohm resistors in series. That is, a 4-ohm resisotr in parallel with a (6+2) ohm = 8-ohm resistor. The equivalent resistance as seen by the current source is = 4 x 8/(4+8) ohms = 2.667 ohms Voltage across the equivalent resistance of 2.667-ohm = 2.667(Is) But this is equal to the voltage across the 4-ohm resistor (resistors in parrallel share the same voltage) Hence, voltage across the 4-ohm resistor = 2.667(Is) The voltage source of 10v gives a voltage across the 4-ohm resistor = 10 x [4/(6+4+2)] v = 3.333 v In order for the 4-ohm resistor to have zero voltage, the voltage given by the 10v source must balanced by the voltagegiven by the current source. Hence, 2.667(Is) = 3.333 i.e. Is = 3.333/2.667 A = 1.25 A
其他解答:B5117735D6B60D95
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