Question 148: Semiconductors and Logic Gates

Question

A common emitter amplifier circuit, built using
an npn transistor, is shown in the figure. Its dc
current gain is 250, R
C
= 1k$\Omega$ and V
CC
= 10 V.
What is the minimum base current for V
CE
to
reach saturation ?
![](https://imagex.cdn.examgoal.net/18hoxe66ijw9693mq/0904f3e1-3bae-4420-aa7a-3dca70fd5609/78823820-8208-11e9-8081-1d558b7f1d26/file-18hoxe66ijw9693mr.png)

Accepted Answer

At saturation state, V
CE
becomes zero
$ \Rightarrow $ i
C
= ${{10V} \over {1000\Omega }} = 10\,mA$
Now current gain factor $\beta  = {{{i_C}} \over {{i_B}}}$
$ \Rightarrow $ i
B
= ${{10\, mA} \over {250 }} =  40\,\mu A$

Answer

100 $\mu $A

Answer

7 $\mu $A

Answer

10 $\mu $A

Answer

40 $\mu $A

Semiconductors and Logic Gates

A common emitter amplifier circuit, built using an npn transistor, is shown in the figure. Its dc current gain is 250, R C = 1k\Omega and V CC = 10 V. What is the minimum base current for V CE to reach saturation ?

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