On the basis of the recent concept of current and power components, for systems with non-sinusoidal currents and/or voltages, power factor correction of the single-phase AC thyristor regulator is investigated. Full and simple mathematical forms for current and power components for both supply and load sides have been derived. Also, expressions for shunt capacitors required, at the supply terminals, to achieve maximum power factor correction have been obtained. Results are obtained for the current and power components of the single-phase AC thyristor regulator for several loading conditions.