買吧! asked in 教育與參考考試 · 1 decade ago

電子學題目:求解理想二極體

這是理想二極體電路,我算出來的答案跟解答不一樣

我把題目和我的解題過程還有解答掃描附在下面連結

幫我看一下我的解題思路哪裡出了問題,謝謝。

http://img261.imageshack.us/img261/2962/002xh9.jpg

圖片看不出清的話請通知一下,謝謝。

Update:

不好意思,題目在以下連結,謝謝。

http://img517.imageshack.us/img517/1030/13069774jl...

Update 2:

補充一下,這題解答的電壓源它是以10V及-10V求解,與題目的15V及-15V有所不同,請以15V及-15V計算。

3 Answers

Rating
  • 1 decade ago
    Favorite Answer

    If D1 is on, the V's voltage is 0V and the current flowing through D2 is (15-0)/5=3A. the current flowing through 10 ohm is (0-(-15))/10=1.5A. The two currents are not equal so V=0(volt) is wrong becasue the current can not flow from D1's k terminal to A terminal.

    Assume D1 is off and D2 is on, the V's voltage is 5V. D2 is an ideal diode and the voltage drop is 0V so the voltage at D1's K terminal is 5V and D1 is off. This is the same as our assumption.

    So D1 is off and D2 is on and the V's voltage is 5V.

    Ans: 5V

  • 1 decade ago

    這兩題D1接法不一樣,首先談解答給的題目,他的D1陰極是接地,而且陽極是接在+15上方,所以他一定會是順偏,所以才導致V1=0。

    另外你自己算的那題D1的陽極反而是接地,而且D2一定是順偏,因為他接在+15上方,然後D2順偏後的陰極電壓也還是高過D1陽極,所以他不會導通,換局話說整個電路D2 ON、D1 OFF。

    所以I=30/15=1mA,V=15-5*2=5V

    2007-09-14 15:09:47 補充:

    你畫的跟解答的電路圖示不一樣的喔,請在確認一次,解答的電路欲求的V是畫在D2陰極下面,而且D1陰極是接地。

    而你畫的D2陽極是接在你欲求的V,而D1陽極反而是接地。

    Source(s): 我是成大電機研究生, 自己
  • ޳
    Lv 5
    1 decade ago

    以目視來看

    V點電壓為 0

    如有錯請告知謝謝~~

    大家再一起研究看看

    2007-09-13 00:06:26 補充:

    就算是15V 也一樣壓

    這種題目先判斷二極體的狀態

    因為題目沒給切入電壓,故不考慮二極體的壓降

    仔細看,一個二極體接至系統最高電壓,一個二極體接至系統最低電壓

    所以想也不用想,兩顆二極體一定全通,然後你就把二極體拿掉

    解電路學,答案就出來了, 0 V 因為拿掉二極體後,中間接地,那電壓當然是 0V囉

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