Ion current detection signal output section for outputting an ion current detection signal including a failure determination signal of an ignition operation is provided, and a failure determination as well as a combustion state can be performed based on this ion current detection signal. The first and second array directions are tilted relative to the cleavage direction of the semiconductor substrate at a predetermined angle \u03b1, as viewed from above the light-receiving surface. The invention further provides a lubricant composition containing said neutral and overbased detergent. The plugs are rotatable around the longitudinal axis of the connector to adjust the orientation of the plug within a nostril relative to a patient’s face, but with sufficient friction to retain the selected position. The associated self-test and switching-control method includes steps of generating a primary clock signal by a phase-locked loop circuit; determining a frequency limit of the primary clock signal; and determining a frequency-dividing condition of the frequency-dividing module according to the frequency limit and the target frequency.