Abstract: Disclosed is a semiconductor structure with an annular collector/subcollector region. The base area with the emitter, is positioned over the collector/subcollector region only, resulting in a smaller base to collector capacitance. Packing density is improved and circuit design flexibility is provided by the ability to change the emitter size without changing the size of the overall structure.

Abstract: A real time monitoring and control system for single or multi-fired combustion systems which permits adjustment of the air fuel ratio in the system for optimized efficiency and minimized pollution content in the exhaust gas, while providing safety control of the combustion process. The system includes a high sensitivity light sensor which is utilized to monitor the combustion flame and provide an electrical output proportional to flame temperature, that is utilized to control the air fuel ratio of the system. The wavelength sensitivity of the sensor is capable of selection, for example by selection of sensor type and/or use of appropriate filters, to monitor a predetermined range or region of the flame emission spectrum in order to enable correlation of the intensity of the emission spectrum of the type of fuel being utilized, i.e., oil or natural gas, with temperature and combustion efficiency.