Abstract: AC power loads such as from transformers, motors, high in-rush heaters, air conditioners, etc., are controlled by the use of bipolar transistors, FET transistors, gate turn-off SCRs and IGBT to turn on the load at zero-cross over and to turn off the load at any point in the sine wave which produces the desired amount of power. This reduces RFI and virtually eliminates di/dt at turn on since both voltage and current start at the same zero cross-over, and hence will improve the power factor. Both analogue and digital logic systems can also be utilized to produce this type of phase control, and a wide variety of possibilities are available such as serial and parallel input, the use of full wave bridge control, etc.