1. When the rms output voltage of the bridge full-wave rectifier is 20 V the PIV across the diode is

28.2

19.3

40

31.42
2. When a Si transistor is in saturation mode the VCESAT is

5V

0.3 V

1V

0V
3. For a two part reciprocal network, the output open-circuit voltage divided by the input current is equal to

B

(B)z12

1/y12

h12

4. The Laplace transform of (tsint) is



22/(s2





5. For step input the output of an integrator is

a pulse

a triangular wave form

a spike

a ramp


6. Two ideal FETs each characterized by the parameters gm and rd are connected in parallel. The composite FET is characterized by

gm/2 and 2rd

gm/2 and 2rd/2

2gm and rd/2

2gm and 2rd

7. A 3-Variable Karnaugh map has

eight cells

three cells

sixteen cells

four cells
8. The number of comparators in a parallel convertor type 8-bit A to D convertor

8

16

256

255
9. The jump address of RST2 instruction in 8085 is

0000H

0008H

0010H

0018H
10. Which I/0 port of 8051 does not have dual function

P0

P1

P2

P3
11. The F0RTRAN statement X=5/10+3.0 15/5.0 2+10 3 will compute the value of X as

48.5

48

34.5

35
12. Which conversion specifier is used with hexadecimal data type








13. The magnetic and electric fields are out of phase by

15°

60°

90°

30°
14. A lossless line of length 500 m has L=10 µH/m and C=0.1 pF/m at 1 MHz. The electrical length of the line is

360°

270°

180°

90°
15. If the carrier of a 100 percent modulated AM wave is suppressed, the percentage power saving will be

50

66.66

150

100
16. Ten bit errors occur in two million transmitted bits. The bit error rate is

2x10-s

5x10-s

5x10-6

2x10-6
17. The value of 0N state voltage of an SCR is approximately

100 V

50V

500 V

2V
18. A silicon photodetector cannot be used to detect the wavelength
1.3 µm

0.633 µm

0.85 µm

1.0 µm
19. Which transducer has infinite resolution
thermistor

LVDT

thermocouple

RTD
20. Which controller produces residual error

0n-off

Integral

Proportional

PID

21.
Assertion Silicon diodes are preferred to germanium diodes for high temperature operation.

Reason The reverse saturation current in a silicon diode is smaller than in a germanium diode.

22.
Assertion In two part networks Y and Z parameters are interrelated and hence need not be defined separately.

Reason Z parameters cannot be defined at high frequency but Y parameters can be defined.

23.
Assertion Multivibrators with 555 are preferred over those with BJT and digital ICs.

Reason 555 provides variation in duty cycle from 0 to 100% and drive a TTL load.

24. Assertion Race around condition occurs in all flip flops.
Reason race around condition occurs in logic circuits due to propagation delay.
25.
Assertion Software interrupts are provided in 8086 microprocessors.
Reason interrupts are generated by exceptions in 8086 microprocessors.
26.
Assertion Break statement is used in switch-case statement.

Reason In switch-case statement use of break prevents unrelated conditions to be skipped.

27.
Assertion An electromagnetic wave propagating in free space along the z direction is necessarily y polarized.

Reason Electromagnetic waves in free space are transverse waves.

28.
Assertion BPSK and QPSK modulation schemes increase the binary data rate in a given bandwidth.

Reason In QPSK modulation each pair of bits is represented by a specific phase.

29.
Assertion Modern optical communication systems use the 1.55 µm band.
Reason Pulse dispersion in optical fibers is minimum at 1.55 µm.

30.
Assertion Thermistor linearity can be improved by connecting a resistor in series with the thermistor.

Reason Connecting a resistance in series with a thermistor will reduce the sensitivity.

31.
Consider the diodes given below.

Germaniun diode

Silicon diode

Schottky diode
Point contact diode
The correct order of increasing cut-in voltage will be


(iii)



(iii)




32.
Consider the following data size.

Byte

Bit

Word
Nibble
The correct order of decreasing data size is












33.
Consider the following guided transmission lines.

Coaxial cable
Metallic waveguide
0ptical fiber
Twisted pair
The correct order in increasing order of bandwidth is












34.
Consider the following electromagnetic waves.

Microwaves

X rays

Ultraviolet radiation
Infrared radiation
The correct order in increasing wave length is












35.
Consider the following amplifier classes.

Class C

Class A B

Class A

Class B
The correct order in increasing efficiencies is










36.
Match List- I with List- II and select the correct answer using the codes given below the lists

List-I List-II

M0SFET Thermal runaway


Breakdown Diodes Isolation


IC Fabrication Gate Capacitance


Transistor Avalanche


Codes










37. Match the List- I with List- II and select the correct answer using the codes given below the lists
List-I List-II

Thevenin's Theorem Transmission Line

Poles and Zeroes Voltage Source

Superposition Theorem S -plane

ABCD Parameters Linear Network


Codes










38. Match List I with List II and select the correct answer using the codes given below the lists
List-I List-II

Differentiator 0.5 V µs

Voltage Regulator Wave shaping

V to F convertor IC 7809

IC 741 noise free transmission


Codes










39. Match List I with List II and select the correct answer using the codes given below the lists
List-I List-II

Counters Totempole output

TTL logic Sequential logic

CM0S Fastest logic

ECL Voo/3


Codes










40. Match List I with List II and select the correct answer using the codes given below the lists
List-I List-II

IC 8279 (i) Serial communication


IC 8251 (ii) Timer counter


IC 8051 (iii) Keyboard controller


IC 8155 (iv) Bit addressable RAM


Codes










41. Match List I with List II and select the correct answer using the codes given below the lists
List-I List-II

8 -Characters register

do while c variable

Compiler and linker executable program

Storage class (iv) executed at least once


Codes










42. Match List I with List II and select the correct answer using the codes given below the lists
List-I List-II

Klystron (i) Negative Resistance

Gunn Diode (ii) Detection

Magnetron (iii) Bunching

PIN Diode (iv) Microwave 0ven


Codes










43. Match List I with List II and select the correct answer using the codes given below the lists
List-I List-II

Amplitude Modulation Frequency interleaving

Frequency Modulation Multiplexer

Time Division Multiplexing Modulation index 1

Frequency Division Multiplexing Modulation index 1


Codes










44. Match List I with List II and select the correct answer using the codes given below the lists
List-I List-II

Intermodal Dispersion Photo diode

Intramodal Dispersion Laser

Responsivity Multimode Fiber

Quantum efficiency Single mode fiber


Codes










45. Match List I with List II and select the correct answer using the codes given below the lists
List-I List-II

Digital Multimeter Phase

0scilloscope Temperature

Bridge 41 digit

LM 35 LorC


Codes









The tunnel diode is a thin junction diode which under low forward bias conditions exhibits negative resistance. Because of thin junction and short transit time, it lends to microwave application. Tunnel diode oscillators were found to be unstable. However, if a high Q cavity is loosely coupled to the diode, a highly stable oscillator is obtained with relative independence to temperature and bias voltage. The application of the tunnel diode was in microwave oscillations and negative resistance amplifier.
The diode voltage-current characteristics illustrate two important properties of the tunnel diode, namely, diode exhibits dynamic negative resistance which is useful for oscillator and amplifier, negative resistance occurs when both the applied voltage and resulting current are low. The tunnel diode is a relatively low power device. The negative resistance is capable of significant power gain.
Tunnel diode amplifiers may be used through out the microwave range as moderate to low noise preamplifiers in all kinds of receivers. Tunnel diode amplifiers are immune to ambient radiation encountered in interplanetary space and hence, practicable for space work.
Gunn discovered the transferred electron effect and this effect was found in Gallium Arsenide and Indium Phosphide. Gunn diodes are used as low power oscillators in microwave receivers. The higher power Gunn oscillators are used as power output oscillators, which include police radars, CW Doppler radars and burglar alarms.
Gunn diodes are greatly superior to IMPATT diodes. Gunn diode amplifiers cannot compete for power output and low noise with GaAs FET amplifiers at frequencies below 30 GHz.
Step recovery diodes are junction diodes which can store energy in their capacitance and then generate harmonics by releasing a pulse of current. These diodes are widely employed in all microwave semiconductor devices. Such a diode is also called a snap off varactor, which is a silicon or GaAs p-n junction diode. Step recovery diodes are used in amplifiers for low-level noise performance in the X band

46. Indicate which of the following diodes does not use negative resistance for operation.

Schottky diode

gunn diode

IMPATT

tunnel diode

47. Which of the following is not used as a microwave detector

Crystal diode

(B)Schottky diode

Backward diode

pin diode

48. 0ne of the following microwave diodes is suitable for low power oscillators only

Tunnel

Avalanche

Gunn

IMPATT

49. For best low level noise performance in the X-band one of the following should be used

a bipolar transistor

gunn diode

a step recovery diode

in IMPATT diode

50. The transferred-electron bulk effect occurs in

Germanium

gallium asenide

Silicon

metal semiconductor junction