Abstract
Tunnel magneto-resistance (TMR) sensors have been widely used in astronautics, automotive electronics, non-destructive testing, biomedicine, etc. However, an effective characteristics test method is still awaited, which to some extent restricts further applications of TMR sensors. This paper presents a static characteristic test system based on Merritt coil. Theoretical calculation and experimental verification are carried out for the coil design. The Merritt coil can generate magnetic field of uniformity better than 1% in a large volume around the central point. The static characteristics of three selected TMR sensors are tested and analyzed. Results show that the TMR sensor has very low hysteresis, and the sensor output is linear with the cosine of the angle between the sensor sensitive axis and magnetic field direction, but the sensitivity of an individual sensor may deviate from the typical value on the datasheet.