Abstract: Data processing and computer systems require continuous monitoring of the primary alternating current power. A power failure must be detected very quickly (within a fraction of a cycle), so that the contents of a volatile memory can be quickly converted into a nonvolatile form. This must occur before power system storage is expended and control is lost. RMS power direction is developed by the product of voltage and current with an integrated circuit multiplier device. When power fails, the circuit indicates a power flow reversal or power equals zero from the detected system current times voltage factor. A retriggerable one-shot in conjunction with a NAND gate is utilized to detect the instantaneous voltage drop to zero and current reversal in order to energize other circuits to protect such volatile data in the event of a power failure.