Resolver, as an electromagnetic sensor, is widely used in many industrial applications. It can detect the position of the rotary part of the electric machines precisely. In commercial resolvers, the excitation winding is connected to the high frequency (HF) AC source. The amplitude-modulated voltages induced in the signal windings need to be demodulated in order to calculate the envelope of the output signals and accordingly detect the position. On the other hand, in PM-resolver, signal windings replaced by Hall-effect sensors to measure the DC magnetic flux which is produced by permanent magnets. In this study, the performance of both AC and DC flux resolvers is investigated under different circumstances. All the simulations are done by the time-stepping finite element method (TSFEM).