What are relays used for in instrumentation?

Relays are essential components in instrumentation because they function as electrically operated switches. Their primary role is to control one electrical circuit by opening and closing contacts in another circuit. This ability enables relays to manage higher power loads with a much lower control signal, allowing for safe and efficient operation of various devices in any control system.

For instance, when a small current is applied to the relay's coil, it activates electromagnetically to either close or open contacts that control a larger circuit, often connected to motors or heavy electrical equipment. This makes relays invaluable in automation processes, allowing for the integration of various control signals without requiring direct connections to heavy machinery.

While amplifying signals is indeed necessary for certain applications in instrumentation, this function is specifically handled by amplifiers rather than relays. Powering sensors is usually achieved through dedicated power supply units designed to provide consistent voltage and current levels, rather than employing a relay. Measurement of flow rates is performed using specific instruments such as flow meters, not by relays, which are not designed to handle such tasks. Thus, the role of relays distinctly aligns with controlling electrical circuits via their switching capabilities.