42. 如右圖所示之電晶體偏壓電路,已知 C1 = 20 µF,C2 = 20 µF,C3 = 60 µF,R1 = 20 kΩ,R2 = 5 kΩ,R3 = 5 kΩ,R4 = 1 kΩ,β = 100,IC電流值約為何?
(A) 0.84 mA
(B) 1.24 mA
(C) 2.14 mA
(D) 3.34 mA
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統計: A(5), B(189), C(14), D(4), E(0) #2499955
統計: A(5), B(189), C(14), D(4), E(0) #2499955
詳解 (共 1 筆)
#4452317
求IC直流,電容開路
簡略求法:
Vb=10*5/(20+5)=2V=Vth
Ie=Ve/Re=(2-0.7)/1K=1.3mA ≒Ic
細求:
Ib=(2-0.7)/[Rb+(1+β)Re]=1.3/105k=0.01238mA
Ic=βIb=100*ib=1.23mA
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