Electronic Compass

FE March 1988 DESIGN ABSTRACTS The contents of this column are based on information obtained from manufacturers in the electronics industry, or their representatives, and do not imply practical experience by Elektor Electronics or its consultants. ELECTRONIC COMPASS Two magneto-resistive sensors and a relatively simple measuring and control circuit form the basis for the design of an all- electronic direction finder. Magneto-resistive sensors: a brief recap The basic structure of the four magneto- resistive elements in the Wheatstone bridge Type KMZ10A is shown in Fig. 1. The sensor elements are essentially meander-shaped, permalloy, tracks with gold stripes. This structure is referred to as a barber"s pole for obvious reasons. Inside the plastic encapsulation of the Type KMZ10A magneto-resistive sensor from Valvo (Philips/Mullard) is a silicon substrate that carries four of such elements connected as the arms of a Wheatstone bridge. The KMZ1OA makes use of the Gauss- effect, i.e....