Deck 6: BJT Frequency Response and Capacitance Analysis

Question 1

Which of the following is not a classification of amplifiers on the basis of their frequency response?

A)capacitively coupled amplifier
B)direct coupled amplifier
C)bandpass amplifier
D)none of the mentioned

Answer 1

none of the mentioned

Question 2

General representation of the frequency response curve is called

A)bode plot
B)miller plot
C)thevenin plot
D)bandwidth plot

Answer 2

bode plot

Question 3

Under what condition can the circuit shown be called a compensated attenuator.

A)c1r1 = c2r2
B)c1r2 = c2r1
C)c1c2 = r1r2
D)r1 = 0

Answer 3

c1r1 = c2r2

Question 4

Which of the following is true?

A)coupling capacitors causes the gain to fall off at high frequencies
B)internal capacitor of a device causes the gain to fall off at low frequencies
C)all of the mentioned
D)none of the mentioned

Question 5

Which of the following is true?

A)monolithic ic amplifiers are directly coupled or dc amplifiers
B)televisions and radios use tuned amplifiers
C)audio amplifiers have coupling capacitor amplifier
D)all of the mentioned

Question 6

During high frequency applications of a B.J.T., which parasitic capacitors arise between the base and the emitter?

A)cje and cb
B)ccs
C)cb
D)ccs and cb

Question 7

During high frequency applications of a B.J.T., which parasitic capacitors arise between the collector and the emitter?

A)no capacitor arises
B)ccs
C)cb
D)ccs and cb

Question 8

During high frequency applications of a B.J.T, which parasitic capacitors arise between the collector and the base?

A)cje and cb
B)ccs
C)c?
D)cµ

Question 9

Which parasitic capacitors do not affect the frequency response of the C.E. stage, of the B.J.T.?

A)cje and cb
B)ccs and cµ
C)cb and cµ
D)no parasitic capacitor gets deactivated

Question 10

Which parasitic capacitors don't affect the frequency response of the C.B. stage of the B.J.T.?

A)none of the parasitic capacitances
B)all the parasitic capacitances
C)some of the coupling capacitors
D)ccs and cb

Question 11

Which parasitic capacitors don't affect the frequency response of the C.C. stage of the B.J.T.?

A)ccs
B)ccs and cb
C)cb
D)ccs and cµ

Question 12

If the transconductance of the B.J.T increases, the transit frequency              

A)increases
B)decreases
C)doesn't get affected
D)doubles

Question 13

If the total capacitance between the base and the emitter increases by a factor of 2, the transit frequency                      

A)reduces by 2
B)increases by 2
C)reduces by 4
D)increases by 4

Question 14

Which effect plays a critical role in producing changes in the frequency response of the B.J.T.?

A)thevenin's effect
B)miller effect
C)tellegen's effect
D)norton's effect

Question 15

If a C.E. stage has a load Rl and transconductance gm, what is the factor by which the capacitance between the base and the collector at the input side gets multiplied?

A)1 + gmrl
B)1 - gmrl
C)1 + 2*gmrl
D)1 - 2*gmrl

Question 16

If a C.E. stage has a load Rl and transconductance gm, what is the factor by which the capacitance between the base and the collector at the output side gets multiplied?

A)1 + 1/gmrl
B)1 - 1/gmrl
C)1 + 2/gmrl
D)1 - 2/gmrl

Question 17

Gain bandwidth frequency is GBP= 3000 Mhz. The cut-off frequency is f=10Mhz. What is the CE short circuit current gain at the ? cutoff frequency?

A)212
B)220
C)300
D)200

Question 18

Which of the statement is incorrect?

A)at unity gain frequency the ce short circuit current gain becomes 1
B)unity gain frequency is the same as gain

Question 19

In an RC coupled CE amplifier, when the input frequency increases, which of these are incorrect?

A)reactance csh decreases
B)voltage gain increases
C)voltage gain decreases due to shunt capacitance
D)an rc coupled amplifier behaves like a low pass filter

Question 20

In Miller's theorem, what is the constant K?

A)total voltage gain
B)internal voltage gain
C)internal current gain
D)internal power gain

Question 21

When applying miller's theorem to resistors, resistance R1 is for node 1 and R2 for node 2. If R1>R2, then for same circuit, then for capacitance for which the theorem is applied, which will be larger, C1 or C2?

A)c1
B)c2
C)both are equal
D)insufficient data

Question 22

Find net voltage gain, given hfe = 50 and hie = 1k?.

A)27.68
B)-22
C)30.55
D)-27.68