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. Closed-loop control uses a measured output to influence the input. Here an ideal comparison turns heat on below a target and off at or above it. An open-loop always-on mode does not make that comparison. The displayed temperature path is invented for explanation; real systems have delays, disturbances and more complex control strategies.
Engineering and scientific investigation · Discover & try
How can a measurement guide a machine?
Reading level 4 of 5 · FluentChange
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Sensor
A component that measures a condition.
Actuator
A component that changes a physical process.
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See how it works
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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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