Historical Document · 1985

US Patent 4,526,477: Piezoelectric Buzzer for Wrist Watches (Daini Seikosha)

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Piezo buzzer mounting and two-tone drive divided from 32,768 Hz; case-back resonance 4–10 kHz; granted 2 July 1985.

Author

Fumikazu Murakami

Year

1985

Type

Historical Document

Credit

US Patent and Trademark Office; via Google Patents.

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