When assessing input devices for control circuits, which device is generally not included?

When it comes to input devices for control circuits, typically, they are characterized by their ability to provide a direct input signal for controlling some aspect of a system. Devices like toggle switches and pushbutton switches function as manual input devices that allow operators to interact directly with the control system by either turning it on/off or sending a signal when pressed.

On the other hand, flow sensors and pressure gauges are types of sensors that provide feedback or measurements based on the physical conditions they are monitoring. While flow sensors can be considered as input devices in certain contexts due to their ability to relay information about flow rate to the control system, pressure gauges are primarily for monitoring rather than providing a direct control signal.

The key to understanding why the flow sensor is included while the pressure gauge is not, lies in their roles in the control system. The flow sensor actively participates in control decision-making by sending signals regarding fluid movement or flow rate, while the pressure gauge does not directly influence the system's operation in the same way. This distinction makes the flow sensor more integral to control circuitry than the pressure gauge, which functions more as a monitoring tool. Thus, the flow sensor is typically included among the input devices, while the pressure gauge is generally excluded from that category.