Magnetfeldsensor

The magnetic field sensor (100) has a current path (116) with a coil portion (102) and another current path (118) with another coil portion (104), where the former coil portion has windings in a winding direction around a magnetic core portion (110). The latter coil portion has windings in another winding direction around another magnetic core portion (112). A signal generator (106) is formed to provide an excitation current which is divided on the former and the latter current paths. An evaluation unit (108) is provided to apply voltage between the coil portions. Independent claims are included for the following: (1) a method for detecting an external magnetic field; and (2) a computer program for executing a detecting method.