PORTABLE_TOY_SIREN

Published:2009/7/22 1:09:00 Author:Jessie | From:SeekIC

Can be assembled in small box as toy for small child. If mercury switch is used for S1, siren comes on automatically when box is picked up. MVBR Q1-Q2 controls rate at which siren wails, while Q3 and Q4 form AF MVBR that produces actual siren sound with frequency varied by triangle waveform on C1. MVBR Q5-Q6 is mono that conducts for preset time period when S1 is dosed, for applying power to siren. Values shown give 12 s of operation before siren is shut off. When carried by child, siren is jostled enough so it keeps recycling.-J. H. Everhart, Super Siren, 73 Magazine, Feb. 1978, p 96-97.



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