Abstract: An integrated thermionic device suitable for use in high temperature, high radiation environments. Cathode and control electrodes are deposited on a first substrate facing an anode on a second substrate. The substrates are sealed to a refractory wall and evacuated to form an integrated triode vacuum tube.

Abstract: An apparatus for measuring temperature or, alternatively, for measuring the flow of thermal power to a substrate maintained at substantially constant temperature. In accordance with the invention there is provided a semiconductor substrate, such as a silicon substrate. A temperature sensing means is formed in the substrate and is operative to generate a first electrical signal as a function of the temperature of the substrate. Means are provided for generating a reference level, and a comparator is reponsive to the first electrical signal and the reference level for generating a control signal. A heater means is formed in the substrate and means are provided for driving the heater means in response to the control signal. Finally, means are provided for measuring the electrical power input to the heater. The measured electrical power input is, in various applications, a useful indication of the temperature of the ambient environment.