What is a control loop and how is feedback used?

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Multiple Choice

What is a control loop and how is feedback used?

A control loop uses feedback to keep a process value near a desired target. It starts by measuring the actual output, compares that measurement to the setpoint (the target value), and computes the error—the difference between them. The controller then uses that error to determine how to change the input to the process, pushing the output back toward the setpoint. This feedback—the measured output information fed back into the controller—drives the corrective action in real time, creating a loop of measurement, comparison, and adjustment. A familiar example is a room thermostat: the sensor reads the current temperature, compares it to the desired temperature, and turns the heater on or off to reduce the temperature difference. This concept is distinct from simply routing power, storing energy in capacitors, or filtering noise, which are different functions and do not describe how the output is continuously adjusted to meet a target.

A control loop uses feedback to keep a process value near a desired target. It starts by measuring the actual output, compares that measurement to the setpoint (the target value), and computes the error—the difference between them. The controller then uses that error to determine how to change the input to the process, pushing the output back toward the setpoint. This feedback—the measured output information fed back into the controller—drives the corrective action in real time, creating a loop of measurement, comparison, and adjustment.

A familiar example is a room thermostat: the sensor reads the current temperature, compares it to the desired temperature, and turns the heater on or off to reduce the temperature difference. This concept is distinct from simply routing power, storing energy in capacitors, or filtering noise, which are different functions and do not describe how the output is continuously adjusted to meet a target.

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