The thermostat is the part of the oven that is charged with regulating the oven's temperature. This component monitors the interior temperature of the oven, turning on and shutting off the heat source according the temperature setting. Thermostats are present in both gas and electric ovens, but their style may vary according to the age and type of oven. The top of the thermostat extends up behind the knob that is used to set the oven temperature; the thermostat can be adjusted by turning this top section if the oven temperature seems inaccurate.
In older ovens, particularly gas models, the top of the thermostat is connected to a long, hollow copper tube that extends into the body of the oven. This tube senses the temperature of the oven by heating up and relaying that heat back to the thermostat. When the thermostat is informed that the oven has reached the desired temperature setting, it shuts off the heat source. When the temperature in the oven cools, the thermostat triggers the heat source, allowing the oven to reheat.
Thermostats in newer ovens are electronic models that are attached to a long probe extending into the oven. The thermostat is wired to a small circuit board inside the oven that controls the heat source. When the probe senses that the oven has reached the correct temperature, it sends a signal to the thermostat's circuit board. That signal tells the oven to turn off the electric burners heating it.