Video narration
What makes a thermostat more than a device that repeats an action? It checks the room, compares its temperature with your desired setting, and switches heating or cooling as needed. That is a feedback loop. Its setpoint is the temperature you want. A sensor measures the room. A controller compares that measurement with the setpoint and decides. Heating or cooling changes the room, and the sensor checks again. The next action depends on the last result: a loop is not repetition; it is correction. But correction must be timed and sized carefully. Too little, and the room responds slowly. Too much correction or delay, and the temperature swings past the target and back-an unstable loop. Loop engineering means choosing measurements, responses, timing, and limits so correction works safely. So why is the thermostat a loop? It measures, compares, corrects, and checks again to reach its setpoint.