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Gate 2019: Revision Test-2

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Question 1

For a p+-n junction diode, how is the junction capacitance Cj dependent on the doping of the n-side Nd?

Question 2

The electron concentration in a sample of n-type silicon varies linearly from 1017 cm-3 at x = 0 to cm-3 at x=4 µm. There is no added electric field. The electron current density is experimentally measured to be -400A/cm2. What is the electron diffusion coefficient?

Question 3

Consider the circuits given below
I.
Description: E:\Gate\Gate-EC\03_Elctro-Devic_B-done_files\image011.png
II.
Description: E:\Gate\Gate-EC\03_Elctro-Devic_B-done_files\image012.png
III.
Description: E:\Gate\Gate-EC\03_Elctro-Devic_B-done_files\image013.png

IV.
Description: E:\Gate\Gate-EC\03_Elctro-Devic_B-done_files\image014.png

Then, which of the following options is correct?

Question 4

In a PLL, lock occurs when the

Question 5

If the gain margin of a certain feedback system is given as 20dB, the Nyquist plot will cross the negative real axis at the point

Question 6

The equation for the time dependence of excess carriers in reading a steady state condition is given by
Description: E:\Gate\Gate-EC\03_Elctro-Devic_B-done_files\image033.png
If Description: E:\Gate\Gate-EC\03_Elctro-Devic_B-done_files\image034.png
Then the excess carrier generation rate is given by g’=____ Description: E:\Gate\Gate-EC\03_Elctro-Devic_B-done_files\image021.png1021 cm-3 s-1.

Question 7

A silicon transistor with common emitter current gain of Description: E:\Gate\Gate-EC\03_Elctro-Devic_B-done_files\image003.png =100 and base doping concentration of Ng= 1019 cm-3 and with minimum breakout open base voltage = 20V.The minimum open emitter junction breakdown voltage must be ____ V given the empirical constant to be equal to 3.

Question 8

For a double hetro junction LED emitting light at a peak wavelength of 1.3 Description: E:\Gate\Gate-EC\03_Elctro-Devic_B-done_files\image002.pngm has radiated and non-radiated recombination time as 40nsec and 120nsec respectively, then the bulk recombination lifetime will be

Question 9

The built-in potential for a silicon p-n junction diode with ND= 1014 cm-3 and NA= 1017 cm-3 for T=300K will be ___V?
(Given intrinsic carrier concentration ni=1.5Description: E:\Gate\Gate-EC\03_Elctro-Devic_B-done_files\image021.png1010 cm3).

Question 10

In the voltage regulator circuit shown in the figure, the op-amp is ideal. The BJT has VBE = 0.7 V and β = 100, and the zener voltage is 4.7 V. For a regulated output of 9 V, the value of R (in Ω) is _______.

Question 11

What is the rank of following controllability of the system
A= B =

Question 12

The open loop transfer function of a unity feedback system is The value of ‘K’ for which the closed loop pole of the system will be located at s= -6 is____

Question 13

An Integrator has transfer function given by If it is required to have gain magnitude unity at frequency = 250 rad/sec then, the gain that must be placed in cascade will be ______.

Question 14

A feedback control system is shown below

If the forward path gain is 400 and feedback gain is 0.05. The percentage change in closed loop gain for 10% change in G is ________

Question 15

The gain margin and the phase margin of a feedback system with are
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Aug 8ESE & GATE EC