A single stage air compressor is defined by which of the following characteristics?

A single stage air compressor is characterized by having one cylinder and one piston. This design allows for the compression of air in a single stroke of the piston, which is efficient for achieving moderate pressures. In this setup, the air is drawn into the cylinder, compressed by the piston’s movement, and then expelled, resulting in a simple and compact mechanism ideal for various applications.

The other options describe features that are not applicable to a single stage air compressor. For instance, having multiple pistons and cylinders pertains to multi-stage air compressors, which are designed to achieve higher pressures by compressing the air in multiple stages. The mention of electric power relates to the type of motor that may drive the compressor, but this does not define the single-stage characteristic itself. Lastly, compressing air through a multi-stage process directly contradicts the definition of a single stage compressor, which only utilizes one compression stage. Hence, the defining feature of one cylinder and one piston clarifies the singular operational mechanism of this type of compressor.