Definition: Device that senses temperature and controls refrigeration equipment to maintain temperature within specified range.
Types:
- **Mechanical**: Bimetal or capillary tube, simple on/off control
- **Electronic**: Digital sensors, programmable, precise control
- **PID Controller**: Proportional-Integral-Derivative, advanced control with minimal temperature variation
Control Methods:
- **On/Off**: Simple cycling, ±2-5°C variation typical
- **Proportional**: Modulates cooling capacity, ±1-2°C variation
- **PID**: Advanced algorithm, ±0.5-1°C variation
Related Terms: Setpoint, Dead Band, Temperature Control, Differential