**BEE Basic Electricity Electronics question paper May 2015** – The B.E.E Mumbai University question paper for semester 1 is given as follows:

### BEE Basic Electricity Electronics question paper May 2015

1 (a) Convert the star circuit into its equivalent delta circuit.

3 M

1 (b) For the given circuit find the Norton equivalent between point A and B.

3 M

1 (c) Draw an a.c. waveform indicate there on and explain (i) instantaneous value, (ii) peak value and (iii) time period for one cycle of the alternating quality.

3 M

1 (d) Differentiate between series and parallel resonance wth respect to

i) Impedance at resonance

ii) Current at resonance

iii) Magnification factor

i) Impedance at resonance

ii) Current at resonance

iii) Magnification factor

3 M

1 (e) Draw the phasor diagram for 3 phase delta connected load with a lagging power factor. Indicate line and phase voltage and currents.

2 M

1 (f) Derive the emf equation for a single phase transformer.

4 M

1 (g) Draw a neat circuit diagram for a full wave bridge rectifier using 4 diodes and the corresponding inputs and output waveforms for voltage.

2 M

2 (a) Find the current through 1 ? resistance using Mesh Analysis.

6 M

2 (b) A coil having a resistance of 10? and an inductance of 40 mH is connected to a 200V, 50 Hz supply. Calculate the impedance of the coil, current, power factor and power consumed.

8 M

2 (c) Draw the phasor diagram of a transformer on no load and explain the various currents and voltage in it.

6 M

3 (a) Three similar coils each having a resistance of 10? and inductance of 0.04 H are connected in star across a 3 phase, 50Hz, 200V supply. Calculate the line current, total power absorbed, reactive volt amperes and total volt amperes.

8 M

3 (b) With the help of a neat diagram explain how short circuit test is conducted on a single phase transformer.

6 M

3 (c) Draw the circuit diagram of a full wave centre tapped rectifier with capacitor filter and the corresponding input and output waveforms.

2 M

3 (d) With the help of a neat diagram explain the output characteristics of an NPN transistor in common emitter configuration.

4 M

4 (a) Using source transformation find the current flowing through the 8? resistance

7 M

4 (b) Find the rms value for the given waveform.

5 M

4 (c) Two wattemeters are used to measure power in a 3? balanced star connected load using the two wattmeter method. The readings of the 2 wattmeters are 500W and 2500W respectively. Calculate the total power consumed by the 3? load and the power factor.

4 M

4 (d) With the help of a neat circuit diagram and input and output waveform explain the working of a half wave rectifier.

4 M

5 (a) Find the current through 8? resistance using Thevenins theorem.

8 M

5 (b) A resistance of 10? and a pure coil of inductance 31.8 mH are connected in parallel across 200V, 50 Hz supply. Find the total current and power factor.

4 M

5 (c) A 5KVA, 1000/200V, 50Hz, single phase transformer gave the following test results.

OC test (hv side): 1000V 0.24A 90W

SC test (hv) side: 50V 5A 110W

Calculate the equivalent circuit parameters of the transformer and draw the equivalent circuit diagram.

OC test (hv side): 1000V 0.24A 90W

SC test (hv) side: 50V 5A 110W

Calculate the equivalent circuit parameters of the transformer and draw the equivalent circuit diagram.

8 M

6 (a) Find the value of current flowing through the 5? resistance using superposition theorem.

7 M

6 (b) A series KLC circuit has the following parameter value: R=10?, L=0.014H, C=100?F Compute the resonant frequency, quality factor. Bandwidth, lower cut-off frequency and upper cut-off frequency.

7 M

6 (c) With the help of a neat circuit diagram and phasor diagram explain the 2-wattmeter method to measure power in a 3? balanced star connected load.

6 M

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