Question

in the figure of transistor as a switch the Vbb supply can be varied from 0V to 5V the si transistor has βdc=250 & Rb=100kohm Rc=1kohm Vcc=5V. assume that when the transistor is satueated Vce=0V and Vbe=0.8. calculate​

Answer 1

Answer:

A) The minimum base current is 20 μA

B) The Vi of the transistor is 2.8v

C) The range of Vi of the transistor is 2.8v to 5v

Explanation:

A transistor is using as a switch. The Vbb supply of the transistor can be varied from 0V to 5V.

The gain of the transistor  βdc=250.

Base resistance is Rb=100kohm.

The resistance of the collector is Rc=1kohm.

The transistor has Vcc=5v.

The figure shows the graph of transistor Vi vs Vo plot and the activation stages of the transistor.

* The total explanation and the math is shown in the paper or in the image attached with this answer. Please go through it.

Answer 2

Answer:

25uA and 3.5 v

Explanation:

Vce =0

VCR=VCR-IcRc

Ic=Vcc/Rc

=5*10^-3A

given /beta dc =Ic/IB

IB=5*10^-3/200

IB=25muA

at input side

VBB=IBRB+VBE

(25mA)(100k )+1v

=3.5v

ANS : 25uA and 3.5 v