Which process transforms electrical energy into pneumatic energy?

The process of transforming electrical energy into pneumatic energy is primarily accomplished through an air compressor. An air compressor operates by using electrical energy to drive a motor, which then compresses air and stores it at a higher pressure. This stored energy can be utilized to perform work in various pneumatic applications, such as powering tools, actuators, and systems that require compressed air.

The other options serve different functions: a valve actuator is responsible for controlling the flow of air or fluid but does not convert energy types, a pneumatic cylinder converts pneumatic energy into mechanical motion, and a filter regulator is designed to control the pressure and quality of the air but does not perform any conversion of electrical energy. Therefore, the air compressor is the correct choice as it is specifically designed for this transformation from electrical to pneumatic energy.