Wiegand sensor

Wiegand sensors are made by wrapping a coil around a Vicalloy wire core, which, due to the hysteresis inherent in the Wiegand effect, induces a pulse in the coil each time the magnetic polarity of the Vicalloy wire core reverses.

[1] They can be used in a range of magnetic sensing applications and have the additional advantage that the energy of each pulse can be harvested.

[2] As a reliable source of consistently timed pulses, Wiegand sensors are used in industrial and commercial flow-metering applications (e.g. water and gas), and also to calculate rotation speed in tachometers (e.g. high-speed trains).

By placing the Wiegand sensor within an oscillating electro-magnetic fields (e.g. from a Helmholtz coil), Wiegand sensors can be used to provide energy for low power applications in environments where high frequency transmission is challenging (e.g. transcutaneous power for medical devices).

[5] Wiegand sensors are commonly used in ‘Batteryless’ rotary encoder technology for self-powered revolution counting.