Temperature control switch according to the working environment of the temperature changes, Temperature sensing element inside the switch, Automatic physical deformation, Resulting in some special automatic control action, An automatic control element that generates an on or off operation, Called automatic reset temperature control switch, Also known as thermal protector or temperature controller, Referred to as thermostat. Or through the temperature sensing element will be temperature,  spread to the temperature controller, The temperature controller automatically send on | off command, Automatic control equipment to run to achieve the desired temperature and energy saving effect.
When Electrical cools down to the reset temperature, Contact automatically closed / open, Electrical appliances return to normal working condition.
Square wiring thermostat switches are automatic reset type,
KSD301 series of automatic reset and manual reset.