A self-powered sensing and transmitting circuit (50) including a power element (44) and a sensing element (46) that is powered by the power element for generating a sensor signal responsive to a local operating environment The circuit also includes a transmitting element (48) powered by the power element for transmitting an output signal responsive to the sensor signal to a receiving location (33, 55) remote from the circuit The power element, sensing element and transmitting element of the circuit are arranged in a generally planar and non-integrated circuit configuration formed on a substrate (57) component exposed to operating temperatures at or exceeding 650° C.