Question 144: Semiconductors and Logic Gates

Question

In the figure, given that VBB supply can vary from 0 to 5.0 V, VCC = 5V, $$\beta $$dc = 200, RB = 100 k$$\Omega $$, RC = 1 k$$\Omega $$ and VBE = 1.0 V. The minimum base current and the input voltage at which the transistor will go to saturation, will be respectively :

Accepted Answer

At saturation, V
CE
= 0
V
CE
= V
CC
$$-$$ I
C
R
C
$$ \Rightarrow $$  I
C
= $${{{V_{CC}}} \over {{R_C}}} = 5 	imes {10^{ - 3}}\,A$$
Given
$$\beta $$
dc
= $${{{{m I}_C}} \over {{{m I}_B}}}$$
I
B
= $${{5 	imes {{10}^{ - 3}}} \over {200}}$$
I
B
= 25$$\mu $$A
At input side
V
BB
= I
B
R
B
+ V
BE
= (25mA) (100k$$\Omega $$) + 1V
V
BB
= 3.5 V

Answer

20 $$\mu $$A and 2.8 V

Answer

25 $$\mu $$A and 2.8 V

Answer

20 $$\mu $$A and 3.5 V

Answer

25 $$\mu $$A and 3.5 V

Semiconductors and Logic Gates

In the figure, given that VBB supply can vary from 0 to 5.0 V, VCC = 5V, $\beta dc = 200, RB = 100 k\Omega , RC = 1 k\Omega $ and VBE = 1.0 V. The minimum base current and the input voltage at which the transistor will go to saturation, will be respectively :

Choose the correct answer: