Introducing the Resolver

Introducing the Resolver What is a resolver? Simply put, a resolver is a transformer with a fixed input winding and two rotating output windings placed orthogonal (90 degrees) to each other. Like a transformer, a resolver only works with AC voltages. If a third output winding is added and they are spaced 120 degrees apart instead of 90, then the resolver becomes a synchro. So, synchros and resolvers are closely related and are often referred to as synchro-resolvers. They are used in for instance robots, tools, weapons, ships, and airplanes as they are not only very precise but also extremely robust and reliable. They support wide temperature ranges and can handle shocks and vibrations. Resolvers excel in harsh environments. If you put an AC voltage on the input winding of a resolver, a voltage develops on the output windings. However, as the output windings can rotate, the amplitude of the output voltage depend on the angle between an output winding and the input winding. One ampli