A magnetic bridge
power sensor including a magnetic bridge that includes: a
magnetic circuit 1 having two ends; magnetic circuits 21a and 21b each having two ends, one of the two ends of each of the magnetic circuits 21a and 21b being connected to one of the two ends of the
magnetic circuit 1; magnetic circuits 22b and 22a each having two ends, one of the two ends of each of the magnetic circuits 22b and 22a being connected to the other end of the
magnetic circuit 1, the other ends of the magnetic circuits 22b and 22a being connected to the magnetic circuits 21a and 21b, respectively; a magnetic circuit 2 having two ends, the two ends being connected to a connection point between the magnetic circuit 21a and the magnetic circuit 22b and to a connection point between the magnetic circuit 21b and the magnetic circuit 22a, respectively; an
excitation coil 3 provided to be able to generate a
magnetic flux in the magnetic circuit 2; and a
magnetic flux detection coil 4 provided to be able to detect the
magnetic flux in the magnetic circuit 1. A current, which is obtained by subjecting a current proportional to a
voltage on a measurement target power line 5 to at least one of an intermittent
processing and an inverting
processing, is carried to the
excitation coil 3. The current of the measurement target power line 5 is carried to a detection target current conductor 5a. An output of the detection coil 4 is synchronously detected by a
signal having a phase synchronized with a cycle of the intermittent
processing or the inverting processing at a frequency twice as high as a frequency of the intermittent processing or the inverting processing.