A sensor measures the temperature. A controller compares that measurement with a chosen target and tells the heater whether to add heat. With feedback, the result is checked again. An always-on heater ignores the comparison and keeps heating. A feedback controller acts on an error or comparison between a measured quantity and a reference, subject to actuator limits. This threshold model has heating but no active cooling, so its capabilities are asymmetric. It isolates the sensor–controller–actuator relationship and omits noise, hysteresis and dynamics needed to design a real control system.
Engineering and scientific investigation · Discover & try
How can a measurement guide a machine?
Reading level 5 of 5 · AdvancedChange
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Sensor
A component that measures a condition.
Actuator
A component that changes a physical process.
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Invented warm-box dynamics and a simple threshold rule. The actuator can add heat but cannot actively cool the box.
What to look for
- The model approaches 22°C and switches the heater off at the target.
- The heater keeps adding heat even when its reading passes the target.
- The heater stays off; this model has no cooling device.
Explain what you noticed
A different system fills a tank. Its sensor already reads above the target level. What fits the stop-at-target feedback rule?
Keep this idea: A feedback loop uses measured results to decide a later action.
Follow the sources
- NASA Goddard — Implementation of a Self-Controlling Heater
- NASA JPL — Robotics: Making a Self-Driving Rover
Source material checked 2026-10-29. Explanations and activities by Nepedia. Source links do not imply endorsement.
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