A thermal electric expansion valve is controlled by what device?

A thermal electric expansion valve, often used in refrigeration and air conditioning systems, is primarily controlled by a thermistor. A thermistor is a type of temperature-sensitive resistor that changes its resistance with temperature variations. This characteristic allows the thermistor to accurately sense the temperature of the liquid refrigerant as it passes through the valve.

When the temperature changes, the resistance of the thermistor alters the control signal sent to the valve, prompting it to adjust the flow of refrigerant based on the thermal load of the system. This adjustment is crucial for maintaining the efficiency of the cooling process by ensuring that the right amount of refrigerant is delivered to the evaporator, promoting optimal heat exchange and system performance.

In contrast, while the other options like resistors, capacitors, and transistors play roles in various electrical circuits and systems, they do not provide the specific temperature-sensitive control required by a thermal electric expansion valve. Therefore, the thermistor is the most suitable choice for this application.