Patent ID: 6522123
Filing Date: 2003-02-18
Classification: G01R

Abstract:
Apparatus for measuring current carried by a conductor, the apparatus comprising;a segment of said conductor having two ends, a differential voltage amplifier having inputs permanently connected to the conductor at two spaced-apart points thereof, constituting said ends of said conductor segment, and providing an output signal representative of a voltage across said ends, and a circuit for converting said output signal of the differential voltage amplifier into a display of said electrical current, said circuit incorporating: at least two amplifiers in parallel relation, each receiving said output signal a selector connected to receive said output signal and to selectively put into operation one of said amplifiers responsive to a magnitude of the current, an analog to digital converter connected to receive an output of that of the amplifiers which is in operation, a programmable memory for storing a calibration table in digital form for correcting static errors as a function of the current, and a microcontroller connected to said programmable memory and receiving a digital output of said analog to digital converter and arranged to drive a display unit.