What type of switch do on-off thermostats use?

On-off thermostats utilize an open contact switch to control the heating and cooling systems in response to the temperature setting. This type of switch functions by closing the circuit to initiate the operation of the heating or cooling system when the measured temperature deviates from the desired set point. When the temperature reaches the set point, the switch opens again, interrupting the circuit and stopping the operation of the system. This on-off operation ensures that the environment remains within the desired temperature range.

The characteristics of an open contact switch are particularly suited for this application as it allows for straightforward and reliable temperature control without the need for more complex mechanisms. The simplicity of this design is key to the effectiveness of many household and commercial heating and cooling systems.