Abstract: An analog display includes a dial and a movable EL pointer positioned adjacent the dial for indicating a measured value. The pointer is an elongated EL lamp having a conductive pin extending through one end of the lamp and about which the lamp pivots. The pin is mechanically secured to the lamp and is electrically connected to the front electrode of the lamp. A hole larger than cross-sectional diameter of the pin is formed in the rear electrode and in the phosphor layer to prevent the pin from shorting the front electrode to the rear electrode. A conductive spring rests on the pin to provide electrical power to the front electrode. Power is supplied to the rear electrode either through a conductive ferrule attached to the rear electrode or through a resilient wiper. The wiper can be attached to the pointer or to the face of the dial. For plural pointers, concentric conductive pins are used with a sliding contact for the rear electrodes.

Abstract: A method and apparatus are employed to detect the onset of soot or smoke formation in a flame exhaust. A pair of oppositely charged electrodes are placed in a flame located where soot formation is likely to occur. Varying voltages are applied across the electrodes and the limiting current, as the voltage is increased, called the saturation current, is measured. Generally, the saturation current decreases for higher fuel-to-air ratios in non-sooting flames. When the threshold for soot formation is approached, a definite saturation current is no longer observed and the current through the electrodes increases rapidly with increasing applied electrode voltage. The detection of the rapidly increasing current during sooting conditions is indicative of the formation of the soot itself.

Abstract: A mass spectrometer is employed to analyze the boron and phosphorus content in silicon or a silicon compound such as SiH.sub.4 or SiHCl.sub.3. According to the preferred embodiment a first non-seeded flame is surrounded by a second seeded flame. The velocities of both flames are approximately the same so that the boundary between them is relatively stable. Small quantities of BO.sub.2.sup.- and PO.sub.2.sup.- are formed in the second flame seeded with a silicon compound. The positively charged inlet orifice of a mass spectrometer is placed in the first flame sufficiently close to the boundary so as to attract negative ions into the instrument. In this manner the relatively small orifice of the sampling cone is not plugged by the SiO.sub.2 particles that are generated in the outer flame and the boron and phosphorus content of the silicon or silicon compound can be measured.