Patent ID: 7550967
Filing Date: 2009-06-23
Classification: G01R

Abstract:
1. A tester for testing at least one magnetic recording head, comprising: a magnetic field generation device having a coil; a magnet driver circuit coupled to the coil of the magnetic field generation device, the magnet driver circuit providing a current to the coil, wherein the current creates a magnetic field that excites the at least one magnetic recording head during testing; a magnetic field sensor positioned to sense the magnetic field and provide a signal indicating a value of the magnitude of the magnetic field, wherein the at least one magnetic recording head is located during testing at a position where the magnetic field has a first magnitude, and the magnetic field sensor is positioned where the magnetic field has a second magnitude that is substantially different than the first magnitude, wherein substantially different is a 2% or greater difference between the first magnitude and the second magnitude; means for receiving the signal indicating the value and controlling the magnet driver circuit to adjust the current provided to the coil based on the signal indicating the value of the magnitude of the magnetic field until the value of the magnitude of the magnetic field is at a desired value; and a measurement circuit that measures an output signal created by the excited at least one magnetic recording head.