FIRE SIREN USES FLASHER


Posted on Feb 6, 2014

Low-drain circuit operating from 1. 5-V cell uses National LM3909 flasher IC to simulate fire-alarm siren. Pressing button produces rapidly rising wail, with tone coasting down in frequency after button is released. Sound from loudspeaker resembles that of motor-driven siren. Volume is adequate for child`s pedal car. -P. Lefferts, Power-Miser Flashe


FIRE SIREN USES FLASHER
Click here to download the full size of the above Circuit.

r IC Has Many Novel Applications, EDN Magazine, March 20, 1976, p 59-66.




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