Unit 1 : Silicon Controlled Rectifier Construction, Static and dynamic Characteristics, specifications/rating of SCR, Triggering Circuits (R, R-C, UJT), Commutation Circuits (class C&D), Protection (over voltage, over current, and Thermal), Gate Turn Off(GTO) Thyristor ( Construction, Working and Application). (Chapter - 1) Unit 2 : Transistor based Devices and DC-DC converter Transistor based devices : MOSFET, IGBT, Construction, working, Static and Dynamic Characteristics, specifications, safe operating area, Latching of IGBT. DC-DC converter : Principle of operation of chopper, classification on the basis of Operating quadrants (A,B,C,D,E), Control techniques: CLC, TRC, PWM and FM Techniques. Analysis of Step up Chopper and Numerical with RLE load. Necessity of input filter, Areas of application, Buck Boost Chopper (Descriptive Treatment). (Chapter - 2) Unit 3 : Single Phase AC-DC Converter Single phase Converter : Fully controlled converter (rectification and inversion mode), Half controlled converter (Semi- converter), Operation of all converters with R, RL load , derivation of Average and RMS output voltage, power factor, THD, TUF. Numerical based on output voltage and current calculations, Effect of source inductance on operation of converter, Concept of overlap angle and voltage drop calculation. Single phase dual converter (Descriptive treatment only). (Chapter - 3) Unit 4 : Three Phase Converter and AC Voltage Regulator Three phase converter : Fully controlled converter, rectification and inversion mode, Half controlled converter (Semi-converter), Operation of all converters with R, RL load, derivation of Average and RMS output voltage, power factor, THD, TUF. Numerical based on output voltage and current calculations. AC voltage regulator : DIAC, TRIAC- four mode operation, triggering of TRIAC using DIAC; Single phase AC Voltage regulator principle with R and RL Load, derivation of Average and RMS output voltage, Concept of two stage AC voltage regulator (With R and R-L load). (Chapter - 4) Unit 5 : Single phase DC-AC Converter (Transistor based) Full bridge VSC, derivation of output voltage and current, Numericals, current source converter with ideal switches. PWM techniques : Single pulse, multiple pulse and sinusoidal pulse modulation with Fourier analysis. (Chapter - 5) Unit 6 : Three phase DC-AC Converter (Transistor based) Three phase VSC using 120° and 180° mode and their comparison, PWM based VSC, voltage control and harmonic elimination techniques (Single Pulse Modulation, Transformer Connection, Multilevel Control, Stepped Wave), Multilevel Converter concept its classification( Neutral Point Clamped Converter, Flying Capacitor Converter, cascaded multilevel converter) comparison between multilevel converters, balancing of dc voltage across capacitor (Chapter - 6)