US Patent 7667934 Adaptive read bias

A read system for a hard disk drive comprising a disk having magnetic fields. The read system comprises a read element, a bias source, a temperature sensor, and a controller. The resistance of the read element changes based on the magnetic fields. The bias source applies a bias level to the read element. The temperature sensor generates a temperature signal indicative of a head ambient temperature. The controller adapts the bias level based on the temperature signal.