To maintain a preset air temperature, an AC/ HVAC system will typically have one or more interior air temperature sensors (Coil Sensor), an ambient (Room sensor) air temperature sensor, further depend on type may have two or more solar load sensors (Solar panel based) 

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Control Panel is where user control the functions of the air conditioner. Displays at the panel may indicate the mode of operation, timer, on/off status, fan speed and also an electronic thermostat that converts the resistance output of temperature sensor into mV/ mA value and display the temperature at both the unit and remote control using a micro-controller