The Principle Of Temperature Controller

There are mechanical and electronic types,
Mechanically, two layers of metal with different thermal expansion coefficients are pressed together. When the temperature changes, its curvature will change. When it bends to a certain degree, the circuit is connected (or disconnected) to make the refrigeration (or heating) equipment work.
Electronic temperature sensing devices such as thermocouples and platinum resistors convert temperature signals into electrical signals, and control relays through circuits such as microcontrollers and PLCs to make heating (or cooling) equipment work (or stop).
There is also a mercury thermometer type, which will have a contact point connected to mercury when the temperature reaches