Resolvers are absolute analog rotary encoders which are ideal for harsh environments. Unlike conventional optical or magnetic rotary encoder (with internal temperature-limiting electronics), the resolver is similar to a transformer in construction and does not incorporate any electronics. An external R/D (resolver-to-digital) interface is required which is also why the resolver can withstand extreme environments (-55°C to +155°C for frame-less resolvers).

There are two types of resolvers: Control Transmitter and Control Transformer. The Control Transmitter features single excitation input to rotor input and sine/cosine stator outputs. The Control Transformer resolver requires both sine/cosine reference stator inputs and rotor output is a phase-shifted sine signal. For new designs, the control transmitter type resolver is recommended as commercial R/D interfaces are available from many manufacturers. For board level designs, R/D conversion ICs are available from Analog Devices and Texas Instruments.

Selecting a resolver is usually determined by shaft size, excitation frequency (a function of the R/D update rate & resolution requirements) and transformation ratio.

  • R11 series are Size 11 (1.1-inch) brushless resolvers with ∅0.120-in shaft
  • RE08-10-15-21-27-35-43-165 series are brushless frame-less (aka pancake resolvers) ranging from Size 08 (∅20mm) to Size 65 (∅165mm)
  • RE15L-A64-1 is a general purpose, single speed, Size 15 resolver with 10mm bore which is available from stock


Contact Micronor Sales with your special resolver requirements.