Patent ID: 10120001

Abstract:
A small-sized power factor measurement apparatus capable of measuring a power factor by one element is desired. The power factor measurement apparatus includes a pair of coupling ends (12) for coupling to a power supply in parallel with a load, two magnetic elements (21, 22) whose changes in electric resistance are different from each other due to the same external magnetic field, a pair of measurement terminals (13) for outputting a differential voltage between the two magnetic elements, a power factor sensor (10) including a pair of sensor terminals (10t) connected to the pair of coupling ends (12), a voltage detector (15) for measuring a voltage between the measurement terminals (13), a low-pass filter (16) connected to the output of the voltage detector (15), a high-pass filter (17) connected to the output of the voltage detector (15), a rectifier (18) connected to the high-pass filter (17), and a divider (19) for dividing the output of the low-pass filter (16) and the output of the rectifier (18).