What is the output voltage of a thermopile under no-load conditions?

The output voltage of a thermopile under no-load conditions is typically around 750 mV. This voltage level is indicative of the thermopile's function as a heat sensor, where it generates a DC voltage in response to a temperature differential across its junctions.

Thermopiles are composed of multiple thermocouples connected in series or parallel, converting thermal energy directly into electrical voltage. The 750 mV reading represents the standard output you can expect when there is no load, meaning that the thermopile is not connected to any consuming device that would affect the voltage output.

This voltage level is critical in applications such as gas appliances, where a certain threshold must be met to ensure proper operation of safety and control systems. Other voltage outputs provided in the options, while plausible, either exceed the typical maximum output for a thermopile under no-load conditions or are less realistic for standard applications in the food service equipment industry. Understanding this output helps technicians troubleshoot and confirm the proper functioning of gas systems in commercial settings.