Transformer for piezoelectric speaker and piezoelectric speaker operative with said transformer

(19)

(11)

EP 0 883 326 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	13.07.2005 Bulletin 2005/28

(43)	Date of publication A2:
	09.12.1998 Bulletin 1998/50

(21)	Application number: 98401302.9

(22)	Date of filing: 29.05.1998

(51)	International Patent Classification (IPC)⁷: H04R 17/00, H01F 1/00, H01F 19/02

(84)	Designated Contracting States:
	AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
	Designated Extension States:
	AL LT LV MK RO SI

(30)

Priority:

03.06.1997 JP 14528097
27.03.1998 JP 8133498

(71)	Applicant: MURATA MANUFACTURING CO., LTD.
	Nagaokakyo-shi Kyoto-fu (JP)

(72)	Inventor:
	Nakamura, Takeshi, c/o Murata Manufact.Co., Ltd Nagaokakyo-shi, Kyoto-Fu (JP)

(74)	Representative: Joly, Jean-Jacques et al
	Cabinet Beau de Loménie 158, rue de l'Université 75340 Paris Cédex 07 75340 Paris Cédex 07 (FR)

(54)	Transformer for piezoelectric speaker and piezoelectric speaker operative with said transformer

(57) The transformer (10) for a piezoelectric speaker includes an E-shaped magnetic core (11). An inner secondary winding (12a) having a number of turns corresponding to approximately one-half of the number of turns of a secondary winding (12) is wound around a shaft portion of the magnetic core (11). A primary winding (13) is wound around the shaft portion of the magnetic core (11) over the inner secondary winding (12a). Further, an outer secondary winding (12b) having a number of turns corresponding to the another half of the number of turns of the secondary winding (12) is wound around the shaft portion of the magnetic core (11) over the primary winding (13). An I-shaped core (16) is provided at the open side of the E-shaped magnetic core (11).

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