Abstract: In an embodiment, the disclosure relates to a method and apparatus for fault monitoring and controlling operation of a discharge nozzle in a large array of discharge nozzles. An exemplary apparatus includes a thin, thermally conductive membrane, with an integrated thin-film electrical heater. When a fixed voltage is applied to the heater, and as the heater heats, the resistance of the heater will increase which will cause a concomitant decrease in the electrical current flowing through the heater. By measuring the resistance of the heater it can readily be determined whether the device is functioning properly.