In the given figure, VB B supply can be varied from 0V to 5V. The Si transistor has β D C=250 and RB=100kΩ ,RC=1kΩ ,VC C=5V Assume that, when the transistor is saturated VC E=0V and VB E=0.8V. The minimum base current for which the transistor will reach saturation is

Question

In the given figure, VB B supply can be varied from 0V to 5V. The Si transistor has β D C=250 and RB=100kΩ ,RC=1kΩ ,VC C=5V Assume that, when the transistor is saturated VC E=0V and VB E=0.8V. The minimum base current for which the transistor will reach saturation is <img class="img-fluid question-image" alt="Question" src="https://cdn.tardigrade.in/q/nta/p-fvewmljrrvsp0c8i.jpg" /> (A) 10μA (B) 20μA (C) 30μA (D) 40μA

Tardigrade Admin · Accepted Answer

At saturation, VC E=0V VB E=0.8V ∴ VC E=VC C-ICRC OlC=(VC C/RC)=(5 V/1 kΩ )=5Î¼A And IB=(IC/β )=(5 Î¼A/250)=20Î¼A

$10 μ A$

$20 μ A$

$30 μ A$

$40 μ A$

At saturation, $V_{CE} = 0 V$
$V_{BE} = 0.8 V$
$∴ V_{CE} = V_{CC} - I_{C} R_{C}$
$O l_{C} = \frac{V _{CC}}{R _{C}} = \frac{5 V}{1 k Ω} = 5 μ A$
And $I_{B} = \frac{I _{C}}{β} = \frac{5 μ A}{250} = 20 μ A$

Q. In the given figure, VBB​ supply can be varied from 0V to 5V. The Si transistor has βDC​=250 and RB​=100kΩ,RC​=1kΩ,VCC​=5V Assume that, when the transistor is saturated VCE​=0V and VBE​=0.8V. The minimum base current for which the transistor will reach saturation is

10μA

20μA

30μA

40μA

At saturation, VCE​=0V VBE​=0.8V ∴VCE​=VCC​−IC​RC​ OlC​=RC​VCC​​=1kΩ5V​=5μA And IB​=βIC​​=2505μA​=20μA

$10 μ A$

$20 μ A$

$30 μ A$

$40 μ A$

At saturation, $V_{CE} = 0 V$
$V_{BE} = 0.8 V$
$∴ V_{CE} = V_{CC} - I_{C} R_{C}$
$O l_{C} = \frac{V _{CC}}{R _{C}} = \frac{5 V}{1 k Ω} = 5 μ A$
And $I_{B} = \frac{I _{C}}{β} = \frac{5 μ A}{250} = 20 μ A$