Re: [問題] 請教這題Vd正確求法

[deathcustom (litron-intl)]

※ 引述《Mopack22926 (阿翔)》之銘言：
: 題目
: http://upload.lsforum.net/users/public/d35517RWe102.jpg
: 小弟照公式算出Vd卻跟答案差很多...
: 是哪邊導錯..

Id = Is*exp(Vd/Vt)

1mA = Is*exp(0.7/25m)

10mA = Is*exp(Vd/25m)

兩者相除

10 = exp[(Vd-0.7)/25m]

ln 10 = (Vd-0.7)/25m

Vd = 0.7 + 25m*ln 10 = 0.7 + 25m*2.3 = 0.7 + 57.5m = 0.7575V ~ 0.76V

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