National Institute of Technology Mizoram

Mid- Semester Examination, Odd Semester - 2023

Solid State Devices (ECL 1301)
grd Semester (ECE) Full Marks: 30 marks Duration: 1hour 30 mins
Answer all 3(Three) Questions. AII Questions carry same Marks
(3 * 10 = 30 Marks)

QUESTION 1
(a) Calculate the energy in terms of kT and Er, at which the difference between the Boltzman
approximation and the Fermi-Dirac function is 5 percent of the fermi function.
(b) Determine the position of the fermi level with respect to valence band energy in p type GsAs at
rbom temperature. The doping concentrations are N, = 5x10' cm' &N= 4x10'5 cm and density
of state is 1.04 x 10! cm at room temperature. [5]

QUESTION 2
ayDerive the continuity equation with reference to excess carrier. Consider a p-type silicon at
Kdoped at N, =Sx10' cm. Assume minority carrier life time is 5x10' and D, =25 cm'/s,
determine the minority carrier diffusion length. [5]

() Derive the expression of built-in potential barrier and electric field across the space charge
Yegion for uniformly dopcd pn junction at zero bias. [5]

QUESTION 3
L9yDerive the expression of depletion width of one sided (p'n) junction. Consider a silicon pn
junction at T-300 Kwith doping concertation Na = 10' cm &N = 10'5 cm'. Given contact
potential at room temperature 0.635, relative permittivity of silicon il1.7 and free space permittivity
is 8.85x104Flem.eles!re deple on aoi dth oP pnum Oie2*3]
oyWitesshort notes on the following:
Y Temperature effect on pn junction ii) Zener Breakdown iil) Avalanche Breakdown [1+2+2]
 National Institute of Technology Mizoram
Mid-Semester Examination, Odd-2023-24
Signals and Networks (ECL 1303)
BTech 3r Semester (ECE) Fall Marks: 30 marks Duration: 1:30 hors
Answer All Questions (3x10 = 30 Marks)
Question 1
a) Determine if the system described by the
following equations are cansal or non-causal.
) y(n) = x(n) + 1 ii) y(n) = x(n²)
x(n-1
b) Determine whether the following (2+2)
systems are time invariant or time variant.
i) y(t) = tx(t)
c) Define BIBO stabie system. Ay(t) =x(t)sin10nt (2+2)
(2)
Qusstion 2
a) Determine the forced response y(n), n20 of
the
y(n)-2y(n-1) - 3y(n-2) = x(n) + 4x(n-1), when thesystem described by the difference equation
input signal is x(n)-2-u(n) and with initial
conditions y(-2)-0, y(-1=5.
(10)
Question 3
a) State superposition theorem. Find the
Iusing superposition theorem.
current through 50 resistor as shown in he given Figure
(2+8)

-s ,

20.2
50
30v
Qov l00.4 - 5(10-)-6 0

Figura 1
-312 1 7 0

20
 National Institute of Technology Mizoram
Mid-Semester Examination, Odd- 2023-24
Electrical and Electronic Measurement (EEL 1308)
B.Tech 3d Semester (EEE&ECE) Full Marks: 30 marks Duration: 1:30 hours
Answer AllQuestions (3x10 = 30 Marks)
Question 1
What is the difference between repeatability and reproducibility of an (1]
instrument?

b) What type of damping torque is used for moving iron instrument and explain [4]
that.

Convert a basic D 'Arsonval movement with an internal resistance of 50 ohnm and (51
a full scale deflection curent of 2 mA into a multirange do voltmeter with
voltage ranges of 0 -10 V, 0- 50 V, 0 -100, Vand 0- 250 V. Draw the circuit
diagram aso.

Question 2
9 Detemine the voltages and currents for the unbalanced Wheatstone bridge (5]
circuit.

R, R
150 Q 50 Q

24 V
100 2

300 Q 250

AKelvin Double Bridge is balanced with the following constants: outer ratio í4]
ams: 100 and 1000. Olhms, inner ratio arms: 99.92/ and 1000,6 hms, link
resistance: 0.1 ohm, standard resistance: 3.77 milliobms, find the unknown
resistance.
c What is the major limitation of a Wheatstone bridge? [1]

Question 3
y praw the vector diagram of Maxwel inductance capacitance bridge.
b Draw the MaxXwell inductance capacitance bridge and derive the quality tactor of 41
the coil.
Y Draw and explain induction type energy meter. (4)
 National Institute of Technology Mizoram
Mid-Senmester Examination, Odd- 2023-24
Digital Logic Design (ECL 1302)
B.Tech 3rd Semester (ECE,EEE, CSE) FullMarks: 30 marks Duration: 1:30 hours
Answer AIl Questions (3x10 =30 Marks)

Quçstion 1
YExpress the Boolean expression f(x,y,z) =Xy +Z+ xyz into its canonical form. (2)
b) Simplify using K-map f= Sm(1,5,6,12,13,14) + d(2,4) and also draw the logic diagram. (3)
c) Implement full adder using NOR gate.
(5)
Question2
)Differentiate between combinational and sequential circuits.
b) Write short notes on Carry Look Ahead adder.
(2)
Define clock signal. Write the excitation table of SR flip flop. (4)
(2+2)
Question 3
sa Implement 16xl MUX using 4x1 MUX.
(3)
byDesign a 4-bit Binary to Gray code converter. (5)
LcYConvert 378.9310 to octal number system. (2)
 NATIONAL INSTITUTE OF TECHNOLOGY MIZORAM
END - SEMESTER EXAMINATION, NOVEMBER 2023
ELECTRICAL AND ELECTRONIC MEASUREMENT (EEL 1308)

3rSEMESTER EEE& ECE FULL MARKS: 50 MARKS DURATION:2:30 HOURS

Auswer AIlthequestions
a) In the AC bridge, slhown in the figure 1, R=10'2 and C=10'F. Ifthe I3)
bridgeis balanced at a frequency o,what is the value of o in rad/s?
b) A Maxwell's Bridge is used to measure an unknown. inductance in
comparison with capacitance. The various values at balance are R2 =
400 S2, R3 = 6002, R4 = 10002, C4 = 0.SuF, Calculate the values of
Rl and L1 Also calculate the values of Qfactor of coil if frequency is Fig. 1
1000 Hz.

) The Four am of Hay's Bridge are arranged as follows AB Coil of unknown impedance. 13]
Arm BC non-reactive resistor of 10002. Am CB Nonreactive resistor of 833 2 with a
standard Capacitor of 0.38 pF. Am DA Nonreactive resistor of 168002. If the supply
Frequency is 50Hz. Determine inductance and resistance at balanced condition.
2. a) The reading of the two watt1meter's connected to measure the total power in a three phase 4]
star connected 400 V system are 4000 W and 6000 W. Find the power factor, the total
power and the line current?
Draw and explain the circuit diagram of electrodynamometer type wattmeter and derive the [6}
torque equation.

3. a) Explain eddy cuirent damping with diagram. 3)

Draw the circuit diagran of induction type single phase encrgy meter. {3)
A lmA meter movernent with an internal resistance of 10092 is to be converted into a 0- {4
10mA. 50mAand 100mA. Calculate the value of shunt resistance required and draw tihe
circuit diagram

4. a) Write four comparisons between electronic andconventional analog meters. [4]

b) Draw the circuit diagran of basic dc clectronic oltmeter.
c) Draw and explain gravity control. (3]

a) Draw the block diagram of cathode ray oscilloscope (CRO) and write the components. i4)
b) Draw the circuit diagran of electrodynamomcter instrument as an ameter.
c) Expluin vertical and borizontal amplifier of GRO.

END
 National Lnstttute of Tech nology Mhzoram
End-Semester Examination, Odd- 2023-24
Signals and Networks (ECL 1303)
BTech 3rd Semester (ECE) Full Marks; 50 marks Duratio:2:30 hoHI
Answer AIl Questions (5x10 =50 Marks)
Qucstion 1
() Determine the trigonometric form of Fourier series of the waveform shown in figure 1. (8m)

T
Figure i
(b) State the conditions for existence of Fourier series.
(2)
Ouestion 2
() Determine the even and odd part of the continuous time
signal x(t)-3+2t+St (2)
(b) Determine power and energy for the continuous time
signals
() x(0=eu(t) (i) x()-e/2+3 (0)
Define unit impulse signal. (2)
Question 3
(Draw the directed graph for the given incidence matrix. (2)
Branches
1-1 0 1 1
2 0-1 0 0 0 -1 1
Incidence matrix=(Nodes) 3 0 0 -1 -1 0 -1 0 -1
4 0 0 0-1, 1
5 1 1 1 1 0 0
(b) In the given circuit figure 2 switch 'k' is opened at t-0. Find the value of v, dv/dt, v/d at
t-0. (6)

1oA

Figure 2
Define non causal systerms. (2)
 Quction4 (2)
()State rociprocity theorem.
ahown below fiure 3. dtraw the transformed círcuit and obtain the expreasion
ntwork (6)
for curront i(t) for t2 0using Laplace transform.
3.0

Pigure 3
(c)Compare series and parallel resonant circuits. (2)

(a) Design a constant k-LPF to have a cut off frequency at 796 Hz when terminated in a 600 Hz
resistance in bothT and r configuration. ()
(b) Find z parameters for the given circuit figure 4. (3)

to

59
V

Figure 4.
 National Institute of Technology Mizoram
End Sennester Examination, Odd Semester -(2023-24)
SOLID STATE DEVICES (ECL 1301)
3rd Semester (ECE) Full Marks: 50marks Duration: 3.00 hours
Answer all 5(Fivc) Questions, AllOucstions Carry Same MarkS
(5 * 10= 50 Marks)

Q1. a) Definc Hall effect. Write the applications of Hall effect. Dcfine the capacitances of (5|
pn junction diode.
b) Asilicon pn junction at T = 300K with zero applicd bias has doping concentrations (5]
Na = Sx 10 cm and N, = Sx10!5 cm. Determine depletion width of n side (x).
depletion width of p side (xp), iotaldepletion width (w) and maximum electric field
(Emax).
Q2. a) Derive the expression of excess minority carrier concentration in forward active mode [5!
for npn transistor in the base region.
b) Explain the following non-idealeffects in BJT with proper characteristics and energy (5]
band diagram:
i) Base Width Modulation ii) Breakdown Voltage

Q3 a) Explain Schottky barrier diode with proper energy band diagram and compare it with 5]
pn junction diode.
b) Describe the working operation of Tunnel diode with energy band diagram and write [5]
its applications.
Q4 a Explain flat band, accumulation, depletion and inversion for two terminal MOS (5]
structure using related cquations and energy band diagram.
b Describe CV characteristics of MOS capacitor in diferent region of operation. (5]
Explain the effect on CV characteristics under the application of high frequency
sinusoidal voltage. Write a short note on effective mobility and CMOS inverter.
Q5 a) Derive the expression of threshold voltage for two terminal n-MOS structure and write [5)
the formula of threshold voltage for p-M0S using analogy.
b) Draw the energy band diagram of n-type MOSFET at threshold inversion point and 51
calculate the maximunm space charge width considering the following parameters.
Fermi potential p = 0.347 V, relative permittivity of silicon ¬, 11.7, free space
permittivity o =8.85x 104 F/cm and doping concentration N, = 106 cm
 National Instituteof Technology Mizoram
End-Senester Examination, Odd- 2023-24
Digital Logie Design (ECL 1302)
B.Tech 3r Semester(CE,EEE,CSE) Full Marks: 50 marks Duration: 2:30 hours
Answer AlIQuestions (5x10m50 Marks)
Question 1
(a) Implement the expression using Multiplexer f(A,B,C,D)- m(0,2,3,6,8,9,12,14). (3)
(b) State De-Morgan'stheorem. (2)
(c) Implement 4-bit priority encoder. (5)
Question 2
(a) With the help of ancat diagram, explain the working ofa three ínput TTL NAND gate (open
collector). (4)
(b) Write short notes on noise margín, fan-out and propagatíon delay of a gate. (6)
Question 3
(a) State atlcast four points of difference between RAM and
ROM memory. (2)
(b) How is race around condition climinated? Explain.
(3)
(c) Design a synchronous3-bit Up-counter.
(5)
Question4
(a) Define resolution. Calculate the resolution (in %) of a6-bit DAC.
(1+2)
(b) Explain SRAM and DRAM in brief.
(7)
Question5
(a) Subtract 100110112 from 110010102.
(b) Write short notes on 4-bit even parity generator. (2)
(4)
() Express the boolean function F=A+ BC as minterm and maxterm. (4)