the coils in a preferred embodiment the pulse durations are empirically determined and stored for each quarter degree interval to obtain even higher levels of accuracy the drive circuitry can be designed to effect a 34 positive zeroing 34 of coils when it is desired to shift a magnetic generator from a high value to a substantially zero value in such shifts the pole tends to retain a residual magnetization which introduces errors in accuracy this source of inaccurancy can be substantially eliminated by including an additional command in the look up table 31 for acute angles requiring a low level of energization for one or more coils instead of commanding a zero current the command can apply a high frequency ac signal so as to produce cancelling effects on the rotor the single magnet indicator of fig1 is an absolute device in that the rotor has a unique magnetic orientation for every angle between 0 u00b0 and 360 u00b0 in alternative forms of the invention employing multiple magnet rotors magnetic symmetries can be introduced which produce ambiguities and in such instances the indicator should be modified to include some type of indexing means fig3 illustrates an alternative form of the invention employing a multiple magnet rotor and indexing means specifically a four pole rotor 40 and indexing means in the form of an indexing magnet 41 are mounted in fixed relation to one.