Abstract: A magnetic circuit for a speaker comprises: a bonded magnet shaped rectangular in top plan view, having on its top face a plurality of grooves formed to extend all the way along two opposing sides thereof and arrayed in parallel with one another at predetermined intervals, and magnetized such that magnetic fluxes at two adjacent grooves are directed inversely to each other; and a plurality of plate-like pole pieces fixedly disposed on the top face of the bonded magnet, and arrayed along the grooves such that two adjacent pole pieces form an air gap located along the center of each groove thereby forming a magnetic gap. And, there is provided a speaker which uses the magnetic circuit thereby achieving a reduced profile.

Abstract: An informing apparatus for a mobile communication apparatus has two magnetic gaps A, B formed in a magnetic circuit, in which voice coils are set respectively. A first vibrant part includes one voice coil connected to a diaphragm, and a second vibrant part includes another voice coil connected, via supporters, to a casing set outside the magnetic circuit, the supporters and the magnetic circuit. A sound receiving function and/or a call-tone receiving function, which is performed with a sound signal and/or a call-tone signal sent to the voice coil 8 in the first vibrant part, and a silent mode call-reception informing function, which is performed with a call-reception signal sent to the voice coil in the second vibrant part whereby the supporters and the magnetic circuit are vibrated thereby making the mobile communication apparatus itself resonate, work independently.

Abstract: A magnetic circuit for a speaker comprises: a bonded magnet shaped rectangular in top plan view, having on its top face a plurality of grooves formed to extend all the way along two opposing sides thereof and arrayed in parallel with one another at predetermined intervals, and magnetized such that magnetic fluxes at two adjacent grooves are directed inversely to each other; and a plurality of plate-like pole pieces fixedly disposed on the top face of the bonded magnet, and arrayed along the grooves such that two adjacent pole pieces form an air gap located along the center of each groove thereby forming a magnetic gap. And, there is provided a speaker which uses the magnetic circuit thereby achieving a reduced profile.

Abstract: An informing apparatus for a mobile communication apparatus is provided, which can be used in a silent mode without a limitation in resonance frequency.

Abstract: A plastic-molded frame 3 has a bottom-closed cylindrical magnetic circuit holding portion 2 which has a positioning projection 6 provided in a central portion on a bottom surface 2a of the magnetic circuit holding portion 2.