Abstract: This invention is a gunshot detection device that provides very reliable inside and outside real-time situational awareness of gunshot events, while reducing Gunshot Detection False Positives and Negatives.

Abstract: A power supply circuit enabling provision of good energy efficiency and downsizing is provided. A power supply circuit 1 according to the present invention includes: input terminals 2, 2 connected to a commercial power supply 10; a winding 4 serially connected between the input terminals 2, 2 via input conductors 3; and a plurality of output terminals 6A, 6B connected to opposite ends of respective windings 4A and 4B resulting from dividing the entire winding 4 into a plurality of parts via output conductors, the respective output terminals 6A and 6B being independently connected to respective loads 20A and 20B.

Abstract: A 24-pulse and 18-pulse composite AC-to-DC converter is a converter using two or more conversion methods in parallel. The converter may include a main rectifier receiving at least a portion of an input AC signal, an autotransformer having an output voltage with lower amplitude than the input AC signal, and a plurality of auxiliary bridge rectifiers, each receiving the output from each leg of the autotransformer. In one embodiment of the invention, the main rectifier may receive a substantial portion of the load current, allowing each of the auxiliary bridge rectifiers to be generally smaller than the main rectifier.

Abstract: A voltage transforming apparatus includes a primary winding receiving an AC voltage, a plurality of secondary windings that are different in number of turns, and a voltage conversion circuit for converting an AC voltage induced in each of the plurality of secondary windings. Each of the plurality of secondary windings includes the first terminal and the second terminal each having a potential that is not fixed. The first terminal and the second terminal are separately provided in each of the secondary windings. The voltage transforming apparatus further includes a switching circuit for selectively connecting the first terminal and the second terminal of each of the plurality of secondary windings to the voltage conversion circuit.

Abstract: An RF impedance transformer having a parallel low-impedance access Eb and serial high-impedance access Eh and intended for connection onto a printed circuit. The transformer includes a multilayer circuit that includes a long side and at least three layers. A first outer layer is separated from a second outer layer of the same thickness by at least one inner layer having a thickness at least four times greater than the thickness of the outer layers, each outer layer comprising an electrical conductor on each surface for forming a microstrip line, the serial high-impedance access Eh and the parallel low-impedance access Eb being on the long side of the multilayer circuit and near to each other so as to limit the area for connection with the printed circuit.

Abstract: A dual output autotransformer is realized by employing a novel topology in which three transformers are wound on a single, high permeability, ferrite, binocular core. The three transformers are (1) an autotransformer; (2) a coupled winding to the autotransformer; and, (3) a transmission line transformer. Within the topology employed, the outputs of the coupled line transformer and the transmission line transformer provide the balanced output (secondary) and the input to the autotransformer forms the unbalanced primary. Such an approach results in a wideband response of from 30 MHz to 3000 MHz or greater with the requisite amplitude and phase balance.

Abstract: A transformer for converting 3 phase AC to 9 phase AC power is provided. The transformer includes first, second and third coils, each coil having a plurality of serial windings coupled together to form a polygon. The transformer further includes first, second and third input terminals each linked to a respective winding of the first, second and third coils. The input terminals are configured to receive a first, second and third phases of input AC power and at least one selected input terminal of the first, second and third input terminals is adjustable to alter a number of turns of the respective winding of the corresponding first, second or third coil on either side of the selected input terminal. The transformer further includes first through ninth output terminals linkable to first through ninth output power lines.

Abstract: A voltage transforming apparatus includes a primary winding receiving an AC voltage, a plurality of secondary windings that are different in number of turns, and a voltage conversion circuit for converting an AC voltage induced in each of the plurality of secondary windings. Each of the plurality of secondary windings includes the first terminal and the second terminal each having a potential that is not fixed. The first terminal and the second terminal are separately provided in each of the secondary windings. The voltage transforming apparatus further includes a switching circuit for selectively connecting the first terminal and the second terminal of each of the plurality of secondary windings to the voltage conversion circuit.

Abstract: A communication interface employing a differential circuit and method of use is disclosed. In one form, a circuit operable to communicate signals via a communication bus can include a differential signaling circuit operable to be coupled to a communication bus. The differential signaling circuit can include a first current carrying element and a second current carrying element. The circuit can also include a shunt circuit including a first transformer. The first transformer can include a primary transformer element and a secondary transformer element. The first transformer can be operably associated with the communication bus.

Abstract: The invention relates to an autotransformer for transforming a three-phase power supply into a nine-phase power supply, notably for use in a rectifier. The autotransformer is a, step-up or step-down transformer. For a step-down application, the three-phase input terminals E1, E2, E3. are connected to one of the three main windings in delta configuration, mounted on respective magnetic branches M12, M23, M31 of a magnetic circuit. Te main winding B12 of one branch has intermediate taps K1, K?1, K?1 from which auxiliary windings X31, Y23, Z31, mounted on the other branches, start. These auxiliary windings produce, on three output terminals A1, B1, C1, voltages one of which is in phase with the three-phase supply voltage at E1, the other phase-shifted by +40°, and the third by +80°. The number of turns in the auxiliary windings and the position of the intermediate taps are calculated so as to obtain this result.

Abstract: An irregular polygon connection of a three-phase autotransformer using only five windings per phase provides a source of nine-phase power suitable for an 18-pulse AC to DC power converter. The windings are connected in a manner to limit the amount of third harmonic current circulating in them. When the autotransformer is used to power a nine-phase AC to DC converter its kVA rating is typically less than 50% of the DC load kW. An additional tap on one of the five windings allows a wide range of AC output voltages to be obtained. Voltages greater than, less than, or equal to the AC input voltage can be obtained. Other multi-phase outputs are feasible. Additional isolated windings can provide means for the invention to operate as an efficient double-wound transformer.

Abstract: Disclosed is a power supply for measuring the line impedance of an underground cable, which includes an input terminal section having a plurality of input terminals, a plurality of autotransformers, a transformer adjustment tap, a plurality of 3rd-harmonics cancellation transformers, and an output terminal section having a plurality of output terminals. The autotransformers are connected respectively to the input terminals. The transformer adjustment tap is connected to all of the autotransformers. The 3rd-harmonics cancellation transformers are connected respectively to the autotransformers. The output terminals are connected respectively to the 3rd-harmonics cancellation transformers.

Abstract: A system and method for reducing harmonics in a circuit is disclosed. The system comprises a main rectifier, ( n 3 - 1 ) auxiliary rectifiers connected to the main rectifier, and an autotransformer connected to both the main rectifier and the auxiliary rectifiers which provides 2n-pulse rectification where n equals the number of phases of the system. The autotransformer generates ( n 3 - 1 ) auxiliary voltage sets, each auxiliary voltage set having an auxiliary voltage amplitude, k, and an auxiliary voltage phase, ?, wherein k = 4 + 2 ? 3 ? cos ? ( ? - 7 ? ? 6 ) and wherein ? = sin - 1 ? ( 3 ? sin ? ? ? ? - 0.5 k ) assuming a main voltage amplitude of one and a main voltage phase of ninety degrees, wherein ? = 180 ? ° n and its integral multiples for all possible real values of k.

Abstract: A low leakage inductance, versatile RF transformer with multiple input/output voltage ratios. The transformer has many applications. For example, and not by way of limitation, the transformer can be used with switching power supplies, RF induction power supplies, and RF plasma power supplies. The efficiency of the transformer is on the order of 99% to 99.7%. These efficiencies have been measured at power levels of 3 kilowatts (KW) to 10 KW.

Abstract: A constant wattage ballast transformer of the isolated type permitting the electrical grounding of a mounting shell of the lamp it powers in which a primary, secondary and auxiliary winding are provided with the primary winding inducing voltage into the auxiliary and secondary windings while being electrically isolated from both these windings and the auxiliary winding electrically connected to the secondary winding to add its induced voltage to that directly induced in the secondary winding from the primary winding.

Abstract: A motor control system and apparatus for providing a desired three-phase voltage in the motor control system include: (1) a main transformer and components that are rated for one nominal voltage input, and (2) a commonly housed input transformer that transforms a different voltage power source to provide the nominal voltage input to the main transformer.

Abstract: Prior VSCF inverters have utilized relatively expensive bipolar transistors and associated base drive circuits together with an input autotransformer which unduly add to the cost and weight of the system. In order ot overcome these problems, a VSCF power converter includes an inverter which utilizes less expensive power switches such as insulated gate bipolar transistors, MOS controlled thyristors or power FET's, together with an output autotransformer coupled between the inverter output and a filter input which eliminates the need for the input autotransformer. The present system is less expensive and lighter than prior VSCF power converters.

Abstract: An auto-transformer has first and second input terminals and first, second and third output terminals, the second output terminal being connected to a center tap of a coil and the first and third output terminals being connected to such points of the coil which are symmetrical with respect to the center tap. The first and second input terminals are connected to such points of the coil which are symmetrical with respect to the center tap. A first group of loads is coupled across the first and second output terminals and a second group of loads is coupled across the second and third output terminals. By equalizing the load currents to the first and second groups, the total current of the auto-transformer can be made significantly small.

Abstract: A variable transformer comprising an annular core with a winding which at the end surface of the core is provided with a circular contact path to be connected with a current brush mounted on a rotor (7). The current brush consists of a contact roller journalled on a shaft pin (11) which from the rotor (7) is directed obliquely downwardly towards the end surface of the core and inwardly towards the axis thereof. The contact roller includes a double-curved contact path (17) for punctiform contact with the contact path (18) of the winding. The reactive pressure provided by said contact urges the contact roller upwardly along the shaft pin (11) which where secured to the rotor (7) is provided with a contact plate (14) that is in heat-conducting communication with the rotor (7). The contact plate (14) includes a plane circular surface (15) against which a correspondingly plane, circular surface (15') of the contact roller about the bore (12) thereof abuts.

Abstract: A wide range voltage regulator circuit exhibiting minimum circuit impedance at maximum output voltage employs a pair of regulating windings in series having their movable contact controlled by a plurality of normally open and normally closed limit switches. The extreme stationary contacts within the first regulating winding are connected with the movable contacts within the second regulating winding to provide a wide range of voltage regulation with negligible impedance at the maximum voltage position.

Abstract: In an electrical three phase variable power supply fed by three phase alternating power and having a three coil adjustable autotransformer connected in wye across the power lines, the autotransformer having taps associated with each of its coils for adjustably connecting to different turns thereof, the power supply having at least one neutral joining the coils of the autotransformer, Zagreb circuit method of varying the power output of the power supply, the Zagreb circuit method comprising providing a supply transformer having a three coil primary, corresponding ends of said primary coils connected to the taps, respectively, and arranging the primary coils in relation to the autotransformer alternatively as follows:A. connecting them in delta across the power lines for a high value of output power;B. connecting them in wye across said power lines in parallel with the autotransformer for a low value of output power; andC.