Air Conditioning Temperature Sensor Probe & Cables

The working principle of the air conditioning ambient temperature sensor is to use a thermistor to sense the temperature of the indoor environment. The thermistor is a component whose resistance value changes with temperature, and its resistance value is proportional to the temperature. In air conditioning systems, the ambient temperature sensor is usually connected to a circuit, which is called a temperature sensor circuit. This circuit contains a constant current source and a voltage comparator.
The constant current source is used to provide a constant current, which generates a voltage through the thermistor, while the voltage comparator is used to convert the voltage signal into a digital signal for processing by the control system. When the resistance of the thermistor changes, the voltage comparator converts this change into a digital signal. This signal is passed to the control system, and the air conditioning system can adjust the cooling or heating operating mode according to changes in indoor temperature, thereby achieving indoor temperature control.

Customized air conditioning temperature sensor wiring harness

The air conditioner temperature sensor is connected in series with a resistor, and generally uses 5V (+3.3V used by some air conditioners) to divide the voltage, and the divided voltage is sent to the CPU. Since the air conditioner temperature sensor uses a negative temperature coefficient thermistor, that is, its resistance decreases when the temperature rises and increases when the temperature decreases. Therefore, the input voltage rule of the CPU is: when the temperature increases, the input voltage of the CPU increases, and when the temperature decreases, the input voltage of the CPU decreases. This changing voltage enters the CPU for internal analysis and processing to determine the current tube temperature or room temperature, and controls the operating status of the air conditioner through internal programs and manual program settings.
Since the sampling voltage sent to the CPU will vary within a wide range as the temperature changes, 25°C is generally used as the standard during design. The sampling voltage is designed to be half the supply voltage to allow sufficient margin for voltage changes due to temperature changes. If the sampling voltage is designed to be too high or too low, it will not be able to properly reflect the current temperature changes.

air conditioning temperature sensor