Abstract: Position sensing apparatus in which an unenergized member, such as a ferrite (60), moves relative to an energized primary coil system (12) and a secondary coil system (11). The primary coil system is single phase energized. The coils (11A, 11B etc.) of the secondary coil system are disposed in series connected pairs (coils 11A, 11G in pair 11/1) interspaced with other pairs (coils 11B, 11H in pairs 11/2) as an array of coils along a path (x) which may be straight, curved, circular etc. The coils in the pairs, which are balanced to give a zero output, form sequences (sequences I, II, III etc.) each of which are terminated with a phase-shift network (PC) to give an incremental phase shift as between one sequence and the next. The incremental phase-shifted outputs are combined to give a progressive phase-shifted output (66) which is representative of the position of the ferrite (60). Ambiguity avoidance, when the progressive phase shift exceeds 360.degree., is preferably provided (FIGS.