Which component should be included in the input box of a block diagram?

The input box of a block diagram is primarily focused on representing the initial information or signal that enters the system for processing. Including a variable being measured in the input box is crucial because it establishes the foundational element that the system will respond to or analyze. This variable can be any measurable physical quantity relevant to the system's operation, such as temperature, pressure, or voltage. By identifying this input first, one can better understand how the system transforms or manipulates that data through subsequent processes.

In contrast, feedback mechanisms, output generators, and process comparators serve different roles within the diagram. Feedback mechanisms are typically associated with the system's output and how it returns to influence the input for better stability and performance. Output generators are concerned with the results produced by the processing stage, showcasing the system's end product. Process comparators function to assess the performance or correctness of a process by comparing it against desired values, which occurs after the input has been processed. Therefore, focusing on the variable being measured in the input box aligns perfectly with the foundational purpose of a block diagram, illustrating how a system receives information for transformation.