What component is primarily affected by temperature changes in HVAC systems?

The thermistor is primarily affected by temperature changes in HVAC systems due to its design and function as a temperature-sensing device. A thermistor is a type of resistor whose resistance varies significantly with temperature. In HVAC applications, it is commonly used to monitor and regulate temperature by providing feedback to the control system.

When the temperature changes, the resistance of the thermistor changes, altering the voltage signal it sends to the HVAC control system. This allows the system to adjust operations accordingly to maintain the desired temperature settings. Thermistors play a crucial role in maintaining system efficiency and comfort by helping to regulate heating and cooling cycles based on real-time temperature data.

In contrast, while capacitors, relays, and compressors are essential components of HVAC systems, they do not directly serve as temperature sensors. Capacitors may influence the operation of a circuit but do not change their operation based on temperature alone. Relays are electromechanical switches that can open or close a circuit based on control signals, while compressors are responsible for pressurizing refrigerant in the system, reacting more to pressure changes than directly to temperature variations.