Thermocouple in a gas grill serves as a vital safety component designed to monitor the pilot flame and prevent uncontrolled gas leaks. When heated by the grill’s pilot flame, the thermocouple generates a small electrical current (typically 10-30mV) via the Seebeck effect. This current keeps the gas supply valve open during normal operation. If the flame extinguishes (due to wind, grease flare-ups, or fuel interruption), the thermocouple cools rapidly, cutting off the electrical signal and triggering an automatic gas shutoff within seconds to ensure safety.