Abstract: An inexpensive flame detector capable of self checking for internal faults, and comprising a detecting photodiode used for detection of a flame, a checking photodiode used for checking function a light source optically coupled to the checking photodiode, an operational amplifier having a feedback resistor connected between the output terminal and non-inverting input terminal thereof, and a decision circuit for receiving the output signal from the amplifier. The checking photodiode is optically isolated from the detecting photodiode and is connected in series, in one embodiment, and in parallel, in another embodiment, with the detecting photodiode. The light source is switched ON and OFF at regular time intervals. The detecting photodiode is connected to the non-inverting input thermal of the operational amplifier. Alternatively, both photodiodes are connected to the non-inverting input terminal.

Abstract: A grounding connector for a shielded cable comprising a backshell, a cap nut, and a ring therebetween, wherein the ring is of a novel design having a single slit and at least three protrusions extending axially toward the cap nut, whereby previously used tube, stepped ring, and spring washers are all eliminated. The invention is thus substantially simplified from the prior art, has enhanced EMI prevention properties, greatly reduced costs, and greatly increased reliability, and improved performance.

Abstract: In a capacitive discharge type ignition apparatus, in which an ignition transformer is used, the impedance of the secondary winding of the ignition transformer is comparatively large. This means the power loss is large and the efficiency, in applying a high power voltage to an igniter plug, is lowered. In this invention, a low impedance bypass circuit is connected in parallel circuit with the secondary winding of the ignition transformer, so that the spark current flows through the bypass circuit. By this arrangement, the power loss in the secondary winding is made to be substantially zero. Thus, a powerful spark is generated in the igniter plug efficiently, reliably and with simple circuitry.

Abstract: A connector backshell structure wherein a wedge-like ring having at least one slit extending along the entire longitudinal length thereof is used for holding a cable shield in tight contact with the tapered inner surface of the connector backshell, and a spring washer is used for elastically urging the ring toward the tapered surface with a cap nut pressing and fixing the spring washer to the open end of the backshell, whereby the contact between the cable shield and backshell is reliably maintained.