2 Marks
Match List I with List II and select the correct answer using the code given below
2 Marks
The value of current gain for the circuit shown below is________.
Q1 has hfe = 25
Q2 has hfe = 25
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Solution
Overall current gain = (1 + hfe)2
= (1 + 25)2
= (26)2
= 676
2 Marks
An unknown impedance Z is shunted across an AC current of value 4 cos (10 t) A.The current source develops a voltage of 9 √2cos(10 t + 45°) V. The value of the impedance is
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Solution
2 Marks
A single range student type potentiometer has a 19 step dial switch where each step represents 0.15 V, the dial resistor are 15Ω. The slide wire of the potentiometer is circular and has 10 turns and resistance of 10Ω each,the slide wire has 100 divisions and interpolation can be done to one fourth of a division. The working battery has a voltage of 5.0 V and negligible internal resistance. The resistance of the series of rheostat in 0hm is ________.
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Solution
Given Dial resistor = 15Ω
Number of turns = 10
Number of division =100
Resistance of each turn =10Ω
To find Series resistance of Rheostat.
Solution Rm= 19 × 15 + 10 = 295Ω
2 Marks
A voltage commutated chopper circuit, operated at 500 Hz is shown below. If the maximum value of load current is 10 A, then the maximum current through the main (m) and auxiliary (A) thyristors will be
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Solution
2 Marks
In the given circuit, the limit of continuous conduction is obtained. Chopping frequency F = 500 Hz, TON= 800ms,then the value of duty cyle α’is ______________.
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Solution
2 Marks
The graph shown below gives the relationship between current, position of the pointer and inductance of moving iron ammeter, then calculate the spring constant of meter,when the current measured by the meter is 1.45 A.
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Solution
k = 43.12 × 10–6Nm/rad
2 Marks
A closed-loop system is shown below.When will the system be very much underdamped?
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Solution
2 Marks
The z-transform of an anti-casual system is \(X(z)=\frac{5-7z}{1+3z-2z^{2}}\) The value of x(0) is __________.
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Solution
Given X(z) = \(\frac{5-7z}{1+3z-2z^{2}}\)
For anti-casual system, x[n] is defined for n ≤ – 1
∴ Hence X[0]=0
2 Marks
After keeping it open for along time, the switch S in the circuit shown in the figure below is closed at t = 0. The capacitor voltage Vc(0+) and inductor current iL(0+) will be
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Solution