What is the output of a control transformer commonly called?

The output of a control transformer is commonly referred to as a difference or error signal. This type of output reflects the difference between the desired setpoint (the target value) and the actual output of a system, such as in control systems for automation. When the system operates, the control transformer measures this difference, which can help in making adjustments to achieve the desired output. The importance of the error signal lies in its function; it is used to create a corrective action that guides the system back towards the setpoint, ensuring stable and accurate performance. This concept is fundamental in control systems, as the correct functioning of controllers relies on continuously minimizing this difference to maintain desired operational levels.