Tunnel magnetoresistance (TMR) is a type of magnetic sensing technology which is increasing in use for various types of sensors and applications.
Christian Fell, general manager of Fraba Inc., said TMR is typically comprised of two ferromagnetic layers which are coupled and separated by a very thin non-magnetic, non-conductive insulation layer. Electrons tunnel through this insulation layer to provide a measurement.
Fraba uses TMR for its position sensors due to the high level of accuracy provided by this technology, as well as the many other benefits it offers.
According to Fell, TMR makes it possible to achieve high resolutions similar to those of optical sensors. This is opening up new application opportunities for position sensors such as rotary encoders, including within hydraulic systems utilized in heavy-duty mobile equipment.
In this interview with Power & Motion, Fell overviews TMR sensor designs and the various benefits, as well as possible application uses, of this magnetic sensing technology.