Abstract: A broadband ultrasonic transducer device (UTD) is disclosed that utilizes a plurality of narrow-band piezo electric elements grouped into single-frequency sub-arrays to provide a relatively simple, highly-reliable deterrent unit (DU) capable of emitting ultrasonic energy over a wide coverage area and at a sound pressure level that meets or exceeds other DU approaches. In an embodiment, the broadband UTD includes a housing portion configured to couple to a plurality of piezo sub-array plates. Each piezo sub-array plate includes a plurality of pockets or cavities to receive respective narrow-band (e.g., 1-3 kHz) piezo electro transducer elements with characteristics, e.g., geometries and material composition, that cause each to emit ultrasonic energy at a particular resonant frequency. A controller of the UTD implements a control scheme to emit ultrasonic energy in a plurality of output modes including a white noise node and a single-frequency mode for deterrence applications.

Abstract: A broadband ultrasonic transducer device (UTD) is disclosed that utilizes a plurality of narrow-band piezo electric elements grouped into single-frequency sub-arrays to provide a relatively simple, highly-reliable deterrent unit (DU) capable of emitting ultrasonic energy over a wide coverage area and at a sound pressure level that meets or exceeds other DU approaches. In an embodiment, the broadband UTD includes a housing portion configured to couple to a plurality of piezo sub-array plates. Each piezo sub-array plate includes a plurality of pockets or cavities to receive respective narrow-band (e.g., 1-3 kHz) piezo electro transducer elements with characteristics, e.g., geometries and material composition, that cause each to emit ultrasonic energy at a particular resonant frequency. A controller of the UTD implements a control scheme to emit ultrasonic energy in a plurality of output modes including a white noise node and a single-frequency mode for deterrence applications.

Abstract: Transient suppression apparatus, which is coupleable in series with an electrical pathway into a potentially explosive environment for limiting current, voltage and energy thereto, comprises: an impedance element coupleable in series with the electrical pathway to conduct current to the potentially explosive environment; at least one first semiconductor element and at least one second semiconductor element coupled in series with the impedance element upstream and downstream of the impedance element, respectively. Both of the first and second semiconductor elements operative to impose a series resistance to the current of the electrical pathway governed by the voltage potential across the impedance element.