What is the process of returning part of the output back to the input for control purposes called?

The process of returning part of the output back to the input for control purposes is known as feedback. Feedback is a crucial concept in control systems, where the output of a system is monitored and used to make adjustments to the input or functioning of that system. This helps in maintaining desired performance levels, stability, and accuracy by allowing the system to self-correct based on the differences between the expected output and the actual output.

For instance, in temperature regulation systems, if the output temperature is higher than the desired setting, the feedback mechanism will detect this and lower the input—such as reducing the heater's power. This continuous cycle of monitoring and adjusting helps ensure that the system maintains optimal performance.

The other options refer to different concepts. Feedforward involves anticipating changes and adjusting inputs proactively without waiting for output feedback. Input processing relates to how input data is handled within a system, while control loop refers to the entire mechanism of measuring outputs, processing them, and adjusting inputs, but does not specifically address the aspect of returning outputs back to inputs.