Earthing or open circuit terminal detection for magnetic read and write head

摘要

The fault detection method involves applying a current to be head while the head is not operating in a write mode. The voltage drop across a resistance (6) connected in parallel with the read-write head (3) is measured. A comparator circuit (7) connected across the terminals of the resistance compares the voltage drop measured across the resistance against a threshold value. The value of the resistance that is connected in parallel with the head is at least ten times be resistance of the head. When the comparator detects that the voltage measured across the head is beyond expected limits, the comparator delivers a logic signal which can be detected, for further processing.