Analog Electronic Circuits

BJT Configuration

Question 1
Marks : +2 | -2
Pass Ratio : 10%
For a BJT, for common base configuration the output characteristics are represented by a plot between which of the following parameters?
VBE and IB
VCE and IC
VCB and IC
VCE and IB
Explanation:
The input signal is applied between the collector and the emitter terminals. Input current flowing is the collector current and hence characteristics are represented by a plot between VCE and IC.
Question 2
Marks : +2 | -2
Pass Ratio : 27%
From the given characteristics, what is the approximate value of IC at IB=30 uA and VCE=10 V?
3 mA
3.4 mA
0 mA
2 mA
Explanation:
At the intersection of IB=30 uA and VCE=10 V, IC=3.4 mA.
Question 3
Marks : +2 | -2
Pass Ratio : 35%
The value of IC is precisely zero when the value of IE is zero.
True
False
Explanation:
When the value of IE is zero, then the value of IC is equal to ICBO which is in the order of microamperes but not zero.
Question 4
Marks : +2 | -2
Pass Ratio : 14%
In a BJT, if the collector-base junction and the base-emitter junction are both reverse-biased, which region is the BJT operating in?
Saturation region
Active region
Cutoff region
Reverse active region
Explanation:
If the collector-base junction and the base-emitter junction are both reverse-biased, then the BJT functions in the cutoff region of the output characteristics.
Question 5
Marks : +2 | -2
Pass Ratio : 2%
For a BJT, for common base configuration the input characteristics are represented by a plot between which of the following parameters?
VBE and IE
VBE and IB
VCE and IC
VCC and IC
Explanation:
The input signal is applied between the base and the emitter terminals. Input current flowing is the base current and hence characteristics are represented by a plot between VBE and IB.
Question 6
Marks : +2 | -2
Pass Ratio : 27%
In a BJT, if the collector-base junction is reverse-biased and the base-emitter junction is forward-biased, which region is the BJT operating in?
Saturation region
Active region
Cutoff region
Reverse active region
Explanation:
If the collector-base junction is reverse-biased and the base-emitter junction is forward-biased, then the BJT functions in the active region of the output characteristics.
Question 7
Marks : +2 | -2
Pass Ratio : 12%
From the given characteristics, what is the approximate value of IC at VBE=0.7 V and VCE=15 V?
3.4 mA
0 mA
2.5 mA
10 mA
Explanation:
From the characteristics, the value of IB at VBE=0.7V is 20uA. Now, from IB=20 uA, we get IC = 2.5 mA.
Question 8
Marks : +2 | -2
Pass Ratio : 2%
For common emitter configuration, which of the following is the correct relation?
IC < IE
IC = βIB
IC = αIE
IC = IE
Explanation:
All the relations hold true i.e. IC = βIB and IC = αIE. As α<1, hence IC < IE.
Question 9
Marks : +2 | -2
Pass Ratio : 6%
In a BJT, if the collector-base junction is forward-biased and the base-emitter junction is forward-biased, which region is the BJT operating in?
Saturation region
Active region
Cutoff region
Reverse active region
Explanation:
If the collector-base junction and the base-emitter junction are both forward-biased, then the BJT functions in the saturation region of the output characteristics.
Question 10
Marks : +2 | -2
Pass Ratio : 6%
Which of the following correctly determines the relation between α and β?
β=α/(1-α)
α=β/(1-α)
β=α/(1-β)
β=α*(1-β)
Explanation:
α and β are related as β=α/(1-α).