Pulse generator using read head with Wiegand wire

摘要

A read head for a Wiegand type wire establishes an asymmetric field to which the wire is subjected. A setting magnet at a first position establishes a sufficiently strong positive field to set the core and shell of the Wiegand wire in a first confluent state. At a second position, the field is sufficiently negative so as to assure that the core switches state thereby establishing a reverse state for the wire. The field does not go strongly negative and thus the state of the shell is not reversed. At a third position, the field becomes sufficiently positive so as to cause the core to reverse its state again thereby switching the wire from its reverse state to its confluent state. This particular switching occurs in close proximity to the pickup coil thereby providing an output pulse in response to the switch of state of the wire from reverse state to confluent state.