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 ?

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 ?

Choose the correct answer: