Original Title: Magnetic Circuits And TransformersElectromagnetism Review of electromagnetism, Magnetic field strength, Magnetic force.Magnetic Circuits Magnetomotive force, Reluctance, Laws of magnetic circuits, Determination of ampere-turns for series and parallel magnetic circuits, Magnetic leakage and fringing, Hysteresis and eddy current losses. Electromagnetic Induction Faraday s laws, Lenz s law, Statically and dynamically induced E.M.F., Energy stored in magnetic field. Transformers Introduction, Principle of working, Construction of single phase transformer, E.M.F. equation, Phasor diagram on no load, Leakage reactance, Transformer on load, Equivalent circuit, Voltage regulation, Power and energy efficiency, Open circuit and short circuit tests, Equivalent circuit parameters estimation. Effect of saturation on exciting current, In-rush current phenomenon.Parallel operation of single phase transformer. Autotransformer Principle of operation, Comparison with two winding transformers.Three Phase Transformers Different winding connections, Voltage and current ratios, Comparative features, Effect of connections on exciting current, Parallel operation. Three winding transformer-Equivalent circuit, Off-load and on-load tap changing transformer, Scott connections.