| 摘要 |
The following specification describes a self-generating electrical pickup to be applied to percussion type musical instruments with vibrating elements of steel or containing ferromagnetic material. The pickup is used in conjunction with an amplifier and loudspeaker to amplify the instrument sound. The pickup makes use of a plurality of pick off coils, one of each is used in proximity to each vibrating element of the musical instrument. Each pick off coil consists of a coil of many turns of fine wire within which is placed an iron core to which is bonded a ceramic permanent magnet. The large surface area of the ceramic magnet adjacent to the musical instrument vibrating element causes large magnetic flux changes in the coil and consequently a large signal voltage which is amplified to drive the loudspeaker. The large signal available, in this design, reduces the effect of 60 Hz hum induced by stray electromagnetic fields. The use of a ceramic magnet provides for a cost effective design. In this design, the plane surface of the ceramic magnet is placed in proximity to the surface of the vibrating element. The length of the iron core, to which the ceramic magnet is attached, exceeds the length of ceramic magnet and said longer iron core acts to extend the magnetic flux into the long solenoidal coil of copper wire, thus allowing for large induced electrical signals when the ceramic magnet surface is adjacent to the vibrating element.
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