A sensor.

摘要

A sensor for detecting the state of motion of an armature in a magnetic field. The sensor comprises a solenoid coil responsive to motion of a magnetic field eminating from the armature to produce a signal, which is then isolated by filtering the total output signal of the solenoid. This sensor can be adapted to provide alarm signals to indicate when the speed of the armature has dropped below an acceptable level e.g. in a magnetic stirrer. Alternatively, the sensor may be employed in a viscosity and/or precipitation determining/monitoring device.