Description
The Honeywell TR21-A is a temperature sensor designed for use in HVAC equipment. It measures temperature by detecting changes in the electrical resistance of a thermistor component within the sensor. As the temperature rises, the resistance decreases. With an average resistance of 10,000 ohms at 25°C and a high beta value, the sensor offers accurate temperature readings (within ±0.2°C) over a wide range. It can also trigger an alert if the temperature exceeds a user-defined setpoint (120°C in this example). This allows HVAC systems to maintain consistent temperatures, improving comfort and energy efficiency for buildings. The sensor’s wide voltage range (5-24V) ensures compatibility with various HVAC control systems.
