🔍 Key Concepts

• final control element in an automatic control system (such as a valve or damper) • Difference between continuous control (smooth movement) and discrete/binary control (only two positions) • What two fixed positions implies about the type of control action

💭 Think About

• Ask yourself: If something only moves between fully open and fully closed, with no in‑between, what type of control is that? • Which option refers to a control that reacts only when a certain limit is passed, instead of adjusting smoothly all the time? • Which term is commonly used for simple thermostats or level switches that just turn equipment fully on or fully off?

✅ Before You Answer

• Identify which option clearly describes only two fixed positions (not a range of intermediate positions). • Eliminate any terms that suggest a zone where no action happens, rather than a simple switch between two states. • Confirm which choice is most commonly associated with thermostats, float switches, and simple start/stop controllers.