Patent ID: 7382122
Filing Date: 2008-06-03
Classification: B82Y,G01R

Abstract:
1. A magnetic sensor comprising: first and second fixed resistors, each of which has a first end connected with a first side of an output line of a DC power source; a first magnetic detecting element which has a first end connected with a second side of the output line of the DC power source, and a second end connected with a second end of said first fixed resistor to function as a sensing portion adapted to face a magnetic detecting medium having a magnetic substance printed thereon; a second magnetic detecting element which has a first end connected with the second side of the output line of the DC power source, and a second end connected with a second end of said second fixed resistor to function as a temperature-compensating portion that is not affected by the magnetic substance printed on said magnetic detecting medium; a magnet that gives magnetic biases to said first and second magnetic detecting elements; and a detection circuit that detects a potential change between a connection point of said first fixed resistor and said first magnetic detecting element and a connection point of said second fixed resistor and said second magnetic detecting element; wherein said detection circuit comprises a single differential amplifier, and detects a concentration of the magnetic substance printed on the magnetic detecting medium based on the detected potential change.