BE3251 Basic Electrical and Electronics Engineering Important Questions

BE3251 Basic Electrical and Electronics Engineering

Important Questions

Unit 1 Part B

1. State and explain Kirchhoff’s voltage law.
2. Calculate the loop currents I_{1} and I_{2} for the circuit shown in Fig.11(a)(i) using mesh analysis. 
   

   

3. Derive the expression for RMS value of an alternating quantity.
4. A series circuit has R = 10Omega L = 50mH and C = 100mu*F and is supplied with 200 V, 50 Hz. Find
   (1) impedance
   (2) current
   (3) power
   (4) power factor
   (5) voltage drop across the each element.
5. Find the current in the 30 resistor in the network shown in fig. 11(a)(i) 
   

   

6. A sinusoidal voltage V = 200 sin 814t is applied to a 10 resistor. Find (1) frequency (2) rms voltage, (3) rms current and (4) power dissipated as heat.
7. Using mesh analysis, determine the current and potential difference across each resistor in the given circuit. The battery has 90 V and the current source 5A. 
   

   

8. Discuss about the working of RLC series circuit and derive the relationships. Give the necessary phasor Diagrams.
   

Unit 2 Part B

1. Derive the E.M.F equation of DC generator.
2. Describe the working principle of DC motor with neat sketch.
3. Explain the construction and principle of operation of three phase induction motor.
4. Assuming necessary parameters, derive the induced E.M.F. equation of a DC generator.
5. Explain the armature resistance speed control of DC shunt motor with a diagram.
6. A transformer has 600 turns of the primary winding and 20 turns of the secondary winding. Determine (1) the secondary voltage if the primary voltage is 140 V with the secondary open. (2) the primary current if the secondary current is 90 A.
7. Compare squirrel cage and slip ring induction motors in detail.
8. Describe the principle of working of DC motor.
9. Describe about the construction of core type and shell type single phase transformers.

Unit 3 Part B

1. Describe the working of a PN junction diode with neat diagram. Also explain its V-I characteristics.
2. Explain with a neat sketch the construction and working characteristics of IGBT.
3. Design a circuit to convert an AC voltage into a DC voltage with a diode full wave bridge circuit and draw the resultant rectified wave form.
4. Explain the operation of BJT in common emitter mode with its characteristics.
5. Describe the working of bridge rectifier. Derive its ripple factor.

Unit 4 Part B

1. Design and explain the working of Gray to BCD converter.
2. Convert 95.062510 binary.
3. Express the function Y=A+B’C in
   (i) canonical SOP and
   (ii) canonical POS form.
4. Explain different error detection technique and error correction codes in detail.
5. Differentiate SOP and POS in Digital Logic.
6. Minimize the expression
   YAB’C+A’B’C + A’ BC + AB’C’+A’ B’C’ Using K-Map
7. Explain about the error detection and correction codes.
8. Simplify the Boolean function, f(W,X,Y,Z)=WX’Y’+WY+W’YZ’ using K-map.

Unit 5 Part B

1. Explain the construction and operation of moving iron attraction type instrument.
2. Describe with the help of block diagram the working of a typical
   DSO.
3. Explain the two wattmeter method of three phase power measurement with a sketch.
4. Describe working of a PMMC meter and its use in measurements.
5. Describe the functional components of DSO with a block
   diagram.
6. Compare current transformer with potential transformers.
7. Describe the construction, working principle of PMMC instruments. Also derive the torque equation.
8. Describe the method to measure three phase power by two wattmeter method.