Abstract: The invention is an improved piezoelectric noise-making and audible signaling device which produces a distinctive 2 KHz tone that is more pronounced and significantly easier to perceive, especially in a noisy environment. The volume of the audible tone is amplified by using two or three sound-amplifying chambers or cavities.

Abstract: The invention is an improved piezoelectric noise-making and audible signaling device which produces a distinctive 2 KHz tone that is more pronounced and significantly easier to perceive, especially in a noisy environment. The volume of the audible tone is amplified by using two or three sound-amplifying chambers or cavities.

Abstract: The invention is an improved piezoelectric noise-making and audible signaling device which produces a distinctive 2 KHz tone that is more pronounced and significantly easier to perceive, especially in a noisy environment. The volume of the audible tone is amplified by using two or three sound-amplifying chambers or cavities.

Abstract: An electronic chime is created by a piezoelectric transducer with an exponentially decaying audio signal. The electronic chime has a power supply, an oscillator, a drive circuit, and a piezoelectric transducer. The drive circuit contains reactive components that function with the piezoelectric transducer to modulate the amplitude of the decaying audio signal. The amplitude modulated audio signal better simulates a mechanical chime.

Abstract: An audio signal is generated that sweeps from a lower frequency to a higher frequency in a substantially linear function. The circuit used to produce this sweeping audio frequency has a stable power supply, a square wave oscillator, a ramp generator, a voltage controlled oscillator, a drive circuit and an audio circuit. The square wave generator is composed of logic gates that generate a square wave with near instantaneous rising and falling edges. The ramp generator creates a sweep drive signal that is a substantially linear triangular waveform.

Abstract: An electronic audio circuit operates a piezoelectric audio transducer to produce a two-tone warbling audio output. The electronic circuit includes an integrated circuit double timer and integrated circuit logic gates. One timer produces a toggling frequency that operates a toggling circuit composed of a logic gate to electrically connect and disconnect an electrical component from a frequency determining network to produce two frequency determining networks. The other timer produces two tones depending upon which frequency determining network is electrically connected to the other timer. The two tone are buffered and then drive a two-element piezoelectric transducer.