Abstract: An electroacoustic transducer includes a permanent annular magnet with a central aperture, with front and back multisided flux plates attached to the annular magnet to complete a magnetic circuit which drives a voice coil and operatively drives a diaphragm. The edges of the front and back multisided fluxed plates defined a surface area of approximately 77 percent of the area bounded by the outer diameter of annular magnet.

Abstract: A valve pin is positioned to open and close a bleed port from the suction side of a carburetor to the exterior of the carburetor in response to variations in electrical control current. Control current is alternatively derived from sensing sources responsive to engine speed or temperature of the engine or engine exhaust. The valve element is connected to and actuated by a magnetic coil operating within the field of a permanent magnet and against a spring bias force to produce valve movement which is directly proportional to changes in the control current throughout the movement of the valve.

Abstract: A loudspeaker magnet structure has a flat annular, torus shaped, permanent magnet with a central cylindrical pole piece of magnetically conductive material extending coaxially through the magnet. A back plate of magnetically conductive material is lapped across the rear side of the magnet and engaged around or over the rear end of the pole piece. A front plate of magnetically conductive material is lapped against the front surface of the magnet and has a central hole of greater diameter than the diameter of the pole piece surrounding the front end of the pole piece.The front surface of the front plate tapers rearwardly to the rear surface of the front plate in continuously decreasing thickness from adjacent to the central hole to closely adjacent to the outer edge of the magnet.