A Resolver is described as which of the following?

• A. A temperature sensor
• B. A pressure gauge
• C. A velocity sensor
• D. A type of rotary electrical transformer used for measuring degrees of rotation.

Answer: (D)

A resolver is an electromechanical angle sensor that works as a rotary electrical transformer to measure how far something has rotated. When the resolver’s rotor (connected to the moving shaft) turns, it modulates the coupling between the rotor and stator windings. By exciting the resolver with a reference AC signal, the stator outputs become two signals that vary with the rotation angle in sine and cosine relationships. This lets you determine the precise degrees of rotation from the electrical signals, and it’s a common choice for precise rotational position feedback in servo systems because it’s rugged and works well in harsh environments.

The other options describe sensors that measure different physical quantities: temperature, pressure, or velocity. They aren’t rotary transformers and don’t provide angle information, so they don’t fit the description of a resolver.