This topic explain the basic concepts of single and three-phase ac system. Unit provides the thorough analysis and derivations as required by topics. Here we find out the voltage current power and power factor for resistive, inductive and capacitive circuits. Also we apply Kirchhoff's voltage and current laws in series and parallel RLC circuit. Complete analysis of balanced three-phase circuit along with the star-delta conversion is given in the unit. Also the appropriate comparison is done between star connection and delta connection.
A very detailed explanation of series and parallel resonance is given in the unit with all important characteristics. Different curves like angle curve, impedance curve, admittance curve, and resonance curve are drawn for both types of resonance. At the end of the unit maximum power transfer theorem is defined for both ac and dc circuit.