Two diodes are connected in series, as shown in the figure below, to share a total d.c. reverse voltage of VD 5 kV. The reverse leakage currents of the two diodes are Is1 =30 mA and Is2 =35 mA. Find the diode voltages, if the voltage sharing resistances are equal, R1 =R2 =100 k.ohm,
the voltage sharing resistances, R1 and R2, if the diode voltages are equal, VD1 =VD2 =VD <img src='./qimages/13251-1a.jpg'> What are the major problems of series and parallel connected diodes Discuss the possible solutions of these problems.

2. Explain the operation of a single phase full bridge converter with load for continuous and discontinuous load currents.

3. Explain the operation of a three-phase full converter. Also derive the expression for its average output voltage.

4. Discuss the working of a three-phase to single phase cycloconverter with neat voltage and current waveforms.

5.(a) With a neat circuit diagram, explain 'anti-saturation' control of base drive for BJT

(b) Describe the current commutation technique to tum off the SCR with a neat sketch and waveforms.

6. Classify the basic topologies of switching regulators and explain the operation of a buck regulator with continuous load current using suitable waveforms.

7. Draw the circuit diagram of a single phase capacitor commutated current source inverter and explain its operation with equivalent circuits for different modes and necessary waveforms.