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US 4,303,908 AGranted
Electronic sounder
AssigneeAmerican District Telegraph Company
InventorsRobert B. Enemark, Aaron A. Galvin, Stephen Marchetti
Life of this patent
Estimating the term…
Abstract
An electronic sounder employs a pair of piezoelectric oscillators tuned to different frequencies to provide loud raucous sound. The sounder is especially suited for providing audible indications of an alarm condition which is sensed by an associated alarm system.
Claims9
An electronic sounder for producing a raucous loud sound with minimum supplied power comprising:
- a first piezoelectric transducer for producing audible sounds having a first frequency in the audible frequency range;
- a second piezoelectric transducer for producing audible sounds having a second frequency in the audible frequency range different than said first frequency by an amount to provide a predetermined audible beat note difference between the first and second frequencies;
- a low power solid state circuit coupled to said piezoelectric transducers and operative to energize the transducers;
- a power source for providing power to said solid state circuit, including a battery and a current limiting circuit, said current limiting circuit including means for providing power to said solid state circuit only when said current limiting circuit is connected to said battery;
- and
- means for selectively connecting the battery to the current limiting circuit to energize the sounder.
3 more elements
An electronic sounder for producing a raucous loud sound with minimum supplied power comprising:
- a first piezoelectric transducer for producing audible sounds having a first frequency in the audible frequency range;
- a second piezoelectric transducer for producing audible sounds having a second frequency in the audible frequency range different than said first frequency by an amount to provide a predetermined audible beat note difference between the first and second frequencies;
- and,
- means for energizing said piezoelectric transducers.
1 more element
Dependencies are inferred from the claim text.