self-regulator
nounUK /ˌself ˈreɡjʊleɪtə/
US /ˌself ˈreɡjəleɪtər/
A self-regulator is someone or something that can control its own actions and feelings.
The little robot is a self-regulator that slows down when it gets too hot.
OTHER MEANINGS
2. A device or system that automatically keeps itself at a steady level.
The thermostat is a self-regulator that keeps the room warm.
3. A person who manages their own emotions and behavior without help.
She is a calm self-regulator, even when things get stressful.
4. A part of the body that keeps its own processes balanced.
The heart acts as a self-regulator, adjusting how fast it beats.