# Consider the discrete-time system shown in the figure where the impulse response of G(z) is g(0)=0,g(1)=g(2)=1,g(3)=g(4) =... =0. This system is stable for range of values of K

1.  [- 1, 1/2]

2.  [- 1, 1]

3.  [- 1/2, 1]

4.  [- 1/2, 2]

4

[- 1, 1]

Explanation :
No Explanation available for this question

# A signal x(t) is given by  Which among the following gives the fundamental Fourier term of x(t)

1.  (4/π) cos ((πt/T) - (π/4))

2.  (4/π) cos ((πt/2T) + (π/4))

3.  (4/π) sin ((πt/T) - (π/4))

4.  (4/π) sin ((πt/T) - (π/4))

4

(4/π) sin ((πt/T) - (π/4))

Explanation :
No Explanation available for this question

# If the loop gain K of a negative feedback system having a loop transfer function K(s + 3)/(s + 8)2 is to be adjusted to induce a sustained oscillation then

1.  The frequency of this oscillation must be 4/√3 rad /s

2.  The frequency of this oscillation must be must be 4 rad /s

3.  The frequency of this oscillation must be must be 4 or 4/√3  rad/s

4.  such a K does not exist

4

such a K does not exist

Explanation :
No Explanation available for this question

# The system shown in figure below can be reduced to the form with

1.  X = c0s + c1, Y = 1/(s2 + a0s + a1), Z = b0s + b1

2.  X = 1, Y = (c0s + c1)/(s2 + a0s + a1), Z = b0s + b1

3.  X = c1s + c0, Y = (b1s + b0) /(s2 + a1s + a0), Z = 1

4.  X = c1s + c0, Y = 1/(s2 + a1s + a0), Z = b1s + b0

4

X = c1s + c0, Y = 1/(s2 + a1s + a0), Z = b1s + b0

Explanation :
No Explanation available for this question

# The value of  where C is the contour |z - i/2| = 1 is

1.  2πi

2.  π

3.  tan-1 z

4.  πi tan-1 z

4

π

Explanation :
No Explanation available for this question

# A single-phase voltage source inverter is controlled in a single pulse-width modulated mode with a pulse width of 150° in each half cycle. Total harmonic distortion is defined as THD = (√(Vrms2 - 1V2)/V1) x 100, where V1 is the rms value of the fundamental component of the output voltage. The THD of output ac voltage wave form is

1.  65.65 %

2.  48.42 %

3.  31.83%

4.  31.83%

4

65.65 \%

Explanation :
No Explanation available for this question

# A voltage source inverter is used to control the speed of a three-phase, 50 Hz, squirrel cage induction motor. Its slip for rated torque is 4%. The flux is maintained at rated value. If the stator resistance and rotational losses are neglected, then the frequency of the impressed voltage to obtain twice the rated torque at starting should be

1.  10 Hz

2.  5 Hz

3.  4 Hz

4.  4 Hz

4

4 Hz

Explanation :
No Explanation available for this question

# A three-phase, 440 V, 50 Hz ac mains fed thyristor bridge is feeding a 440 V dc, 15 kW. 1500 rpm separately excited dc motor with a ripple free continuous current in the dc link under all operating conditions.Neglecting the losses, the power factor of the ac mains at half the rated speed,is

1.  0.354

2.  0.372

3.  0.90

4.  0.955

4

0.354

Explanation :
No Explanation available for this question

# A single-phase, 230 V, 50 Hz ac mains fed step down transformer (4 : 1) is supplying power to a half-wave uncontrolled ac-dc converter used for charging a battery (12 V dc) with the series current limiting resistor being 19.04 . The charging current is

1.  2.43 A

2.  1.65 A

3.  1.22 A

4.  1.0 A

4

2.43 A

Explanation :
No Explanation available for this question

# A three-phase synchronous motor connected to ac mains is running at full load and unity power factor. If its shaft load is reduced by half, with field current held constant, its new power factor will be

1.  unity

3.  lagging

4.  dependent on machine parameters

4