作者fairwarning (一轮明月与蓝夜!!)
看板Grad-ProbAsk
标题[理工] [电子]-电流镜
时间Wed Sep 16 12:45:17 2009
[电路图]
http://www.wretch.cc/album/show.php?i=fairwarning&b=4&f=1893012287&p=0
[题目]
For the current mirror,the two BJTs are idential expect that the emitter area
of Q2 is three times of that of Q1.
Assume that Q2 is active , Vbe=0.6V , and the Early voltage is infinite;
(1)if β=∞ ,IL=?
(2)if β=10 ,IL=?
[解答]
(1) IL=0.6mA (2) IL=0.428mA
为了增加题目文完整度...顺便打(1)打出..
请问大家(2)要怎麽解呢?
谢谢大家的帮忙~~ 谢谢!
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※ 发信站: 批踢踢实业坊(ptt.cc)
◆ From: 140.127.150.126
1F：推 eageoneal:列两端BASE电流 右边为左边3倍 再利用IC=BIB 列方程式 09/16 13:42
2F：→ eageoneal:设左边IB为X 右边IB为3倍X 中间为3+1=4X 左边IC为 10X 09/16 13:44
3F：→ eageoneal:{5-(-4.4)}/47=14X X=0.0142mA 锁球极为右边IC=30X= 09/16 13:46
4F：→ eageoneal:=0.42857...mA 09/16 13:46
5F：→ fairwarning:谢谢喔..我自己试试看!! 09/16 16:32