GATE EC 2018 Exam: Revision Test 4 for ESE & GATE EC Exams

Question 1

In the given circuit, the silicon transistor has β = 75 and a collector voltage V_C = 9V. Then the ratio of R_B and R_C is ________.

Question 2

An AM signal is detected using an envelope detector. The carrier frequency and modulating signal frequency are 1 MHz and 2 KHz respectively. An appropriate value for the time constant of the envelope detector is

Question 3

In successive approximation of A/D converter the offset voltage is equal to LSB that gets added to D/A converter’s output which happens in order to:

Question 4

The system shown in the figure is

Question 5

In the 4 × 1 multiplexer, the output F is given by F = A ⊕ B. Find the required input ‘I₃I₂I₁I₀’.

Question 6

In a PCM system, if the code word length is increased from 6 to 8 bits, the signal to quantization noise ratio improves by the factor

Question 7

Two 8-bit ADCs, one of single slope integrating type and other of successive approximation type, take T_A and T_B times to convert 5V analog input signal to equivalent digital output. If the input analog signal is reduced to 2.5V, the approximate time taken by the two ADCs will respectively, be

Question 8

White noise with two sided

is applied to an ideal low pass filter with cut off frequency B rad/sec. Find B so that the output average noise power is 15 watts

Question 9

What will be the expression of reluctance in circular magnetic circuit of length as 2πr with N number of turns, having cross sectional area A, when magnetic flux is flowing around it?

Question 10

In a curl of vector field, what will be the condition for a field to be irrotational?

Question 11

Which of the following statement holds for the divergence of Electric & Magnetic Flux densities

1) Both are zero
2) These are zero for static densities but not zero for time-varying densities
3) It is zero for the electric flux density
4) It is zero for the magnetic flux densities

Question 12

The hysteresis loop of a magnetic material has an area of 5 cm² with the scales given as 1 cm = 2 AT and 1 cm = 50 mWb. At 50 Hz, the total hysteresis loss is

Question 13

The input signal V_in shown in the figure is a 1 KHz square wave voltage that alternates between +7V and -7V with a 50% duty cycle. Both transistors have the same current gain, which is large. The circuit delivers power to the load resistor R_L. What is the efficiently of this circuit for the given input? Choose the closest answer.

Question 14

The block diagrams of two types of half wave rectifiers are shown in the figure. The transfer characteristics of the rectifiers are also shown within the block.

It is desired to make full wave rectifier using above two half-wave rectifiers. The resultant circuit will be

Question 15

The block diagram of a closed loop control system is given by figure. The values of K and P such that the system has a damping ratio of 0.7 and an undamped natural frequency ω_n of 5 rad/sec, are respectively equal to