What is the Difference Between a Temperature Sensor and a Thermal Switch (Thermal Interrupter)?
In automotive systems and many industrial applications, different devices are used to control temperature, among them the thermal switch and the temperature sensor. Although they may look similar at first glance, they perform very different functions.
Thermal Switch
A thermal switch is a thermal interrupter that opens or closes an electrical circuit when a specific temperature is reached. Its main role is safety or control: for example, activating the radiator fan when the engine reaches a certain temperature, or cutting off current flow to prevent overheating. It operates within fixed ranges, acting as an “on/off point,” without providing detailed temperature information.
Temperature Sensor
On the other hand, a temperature sensor (such as NTC, PTC sensors, or thermistors in vehicles) converts temperature into a proportional electrical signal. This signal is interpreted by the electronic control unit (ECU) or other systems, which can precisely regulate fuel mixture, ignition, injection, and other parameters. Unlike the thermal switch, it is not a simple interrupter but a device that measures variable values and transmits them in real time.
In Summary
The thermal switch controls based on fixed thresholds, while the temperature sensor measures and reports continuous values. Both are essential, but they serve complementary roles in the operation and safety of systems.
