The book contains Concept OF Thyristors - Silicon Controlled Rectifiers (SCR's) - Two transistor analogy - Static and Dynamic characteristics - Turn on and turn off methods - UJT firing circuit - Series and parallel connections of SCR's - Snubber circuit details - Line Commutation and Forced Commutation circuits - Power MOSFET, Power IGBT, their characteristics and other form of thyristors. Phase control technique - Single phase Line commutated converters - Bridge connections - Half controlled converters with R, RL and RLE loads - Derivation of average load voltage and current - Numerical problems. Semi and Fully controlled converters, Bridge connections with R, RL loads - Derivation of average load voltage and current. Three phase converters - Three pulse and six pulse converters - Bridge connections average load voltage with R and RL loads - Effect of Source inductance - Dual converters (both single phase and three phase) - Waveforms - Numerical Problems.