Abstract: A high-frequency switch circuit is presented. The invention includes a pair of switches, a pair of inductors, and a pair of diodes. Inductors are electrically connected in series between the switches which are thereafter electrically coupled to a power source. Switches are electrically connected to gate drivers so as to control and coordinate the cycling of switches between ON and OFF states. Inductors are also electrically connected to an output thereby communicating a voltage waveform thereto. In some embodiments, it may be desired to electrically connect the inductors to an output circuit to further modify the waveform. Diodes are likewise electrically connected about the switches and inductors. The present invention is applicable to a variety of circuits having a totem pole arrangement of switches sequentially cycled ON and OFF, examples including but not limited to half-bridge, full-bridge, and hybrid configurations.

Abstract: A gate drive circuit capable of providing both positive and negative drive from a DC power supply is presented. The circuit includes an isolator stage, a driver stage, an optional tuning stage, an offset stage, a shaping stage, and a switching stage, each electrically coupled in the order described. The isolator stage provides electrical isolation from signal level circuitry. The driver stage boosts the power within the signal from the isolator stage. The tuning stage slows rising and falling edges along the signal from driver. The offset stage shifts the unipolar gate drive signal from the tuning stage into the negative voltage range. The shaping stage modifies the signal from the offset stage so as to ensure squared transitions. The switching stage enables voltage control. The described circuit is applicable to electronics utilizing a variety of voltage controlled switching devices.

Abstract: This invention features a method for encoding surface acousting wave (SAW) delay lines. The method uses a split-electrode transducer as a programmable reflector. When shorted out, it does not reflect surface waves. When open-circuited, it partially reflects incident surface waves. As manufactured by conventional photolithographic methods, each of several such transducers is shorted out by a fusible link. In the as-manufactured state, the array of shorted transducers produces no reflection of surface waves. If a fusible link is destroyed by passage of electric current or other means, the corresponding transducer becomes a partial reflector. The status of these switchable reflectors may be read by exciting a separate launch transducer with a burst of electromagnetic energy containing substantial energy at the basis operating frequency of the SAW transducers or at suitable harmonics.

Abstract: A theft resistant security system for motor vehicles. The system has a receptacle with a coupling coil. A surface acoustical wave device associated with the receptacle for relative movement thereto is also provided. The SAW device has a code and its own coupling coil for interaction with the receptacle coupling coil. A testing mechanism is connected to the receptacle for determining whether the code of the SAW device is valid for operation of the motor vehicle.

Abstract: A controller for a motor vehicle security system. The controller has a SAW device adapted to receive a signal and to generate a reply signal. A decoder is connected to the SAW device for decoding the reply signal. A comparator compares the reply signal to a previously stored value and an enabling device enables operation of the motor vehicle when the predetermined value and the decoded reply signal are successfully compared.

Abstract: An electrical connecting device for use with a multiple layered circuit-containing device wherein at least two layers of the multiple layered circuit-containing device each contain a circuit including a plurality of circuit contacts to be electrically connected by the electrical connecting device. The electrical connecting device includes an upper longitudinal peripheral surface joined to a lower longitudinal peripheral surface by an intermediate longitudinal surface to form an elongated member which has a Z-shaped configuration in cross section and is formed from a plurality of Z-shaped connectors shaped from each other in a predetermined amount to effect a moire pattern when superimposed relative to the circuit contacts of at least one of the layers.

Abstract: The above and other objects, advantages and capabilities are achieved in one aspect of the invention by an output circuit for an electronic ballast system. The circuit includes N sets of output connections for accepting N lamps. The lamps are driven by an output autotransformer coupled to the lamps through a feedback winding that is used to apply a feedback signal to an inverter drive circuit. Capacitive impedances are coupled across the lamps so that the capacitances, the lamp filaments, the feedback winding, and the output transformer form a circuit loop. The capacitances are chosen to have an impedance, at the inverter operating frequency, less than the pre-ignition impedance of the lamps and greater than the post-ignition impedance.

Abstract: The above and other objects, advantages and capabilities are achieved in one aspect of this invention by a drive scheme for a plurality, that is, for N, where N-2, flourescent lamps. The drive circuit comprises (N+1) pairs of output terminals, each comprising associated first and second individual terminals. An output transformer is coupled at one end to the (0,1).sup.1 terminal and at another end to the (0,1).sup.N+1 terminal. N impedance elements, typically capacitors, are coupled across associated pairs of lamp filaments in a fashion whereby each impedance element is coupled at one end to the second terminal of one pair and at another end to the second terminal of the succeeding pair. To wit: The first impedance element is coupled between the second terminal of the first pair, and the N.sup.th element is coupled between the second terminal of the N.sup.th pair and the second terminal of the (N+1).sup.th pair.

Abstract: An output configuration for an electronic ballast system includes means for effecting independent selection of both pre- and post-ignition lamp filament voltages. The primary of a filament voltage control transformer is coupled to lamp filaments so as to induce a voltage in the transformer secondary windings in relation to the lamp filament current. The secondary windings are arranged so that the voltage induced therein adds to the voltage provided to the lamp filaments by filament drive windings on the ballast output transformer.

Abstract: A delayed starting circuit for an electronic ballast system that includes an inverter coupled to a secondary voltage source. The starting circuit includes a voltage divider having an input coupled to a charge storage capacitance in the voltage source and an output coupled through a semiconductor switching device to an input of the inverter. The switching device remains non-conductive until the capacitance has been substantially charged, thereby protecting the inverter from transients encountered as a surge of charge is delivered to the capacitance subsequent to the initial energization of the ballast circuit.

Abstract: A dimmer circuit for an inverter-driven electronic ballast system. The ballast includes an output transformer having a primary winding coupled to the inverter output and a secondary winding adapted to be coupled to a lamp filament winding for supplying power to the filament. An interstage transformer has a primary winding adapted to be coupled to a lamp filament and a secondary winding coupled to an inverter input for applying a feedback signal derived from the filament current at that input. The dimmer circuit is in the form of a feedback loop that includes a winding on the primary of the output transformer, a winding on the primary of the interstage transformer, and a variable impedance coupling those windings. Varying the impedance necessarily varies the total feedback loop impedance and therefore the amount of feedback applied at the inverter output and, inversely, the power supplied to the lamp filament.

Abstract: An improved drive scheme for a pair of push-pull inverter transistors in an electronic ballast circuit. The inverter output is coupled through a series resonant circuit comprising a capacitor and the primary winding of an output transformer. The resonant circuit is coupled to the inverter output through an additional winding on the primary of an interstage so that a component of the loop current is fed back to the bases of the push-pull transistors, thereby compensating for phase errors in the drive signal applied at the inverter input.

Abstract: An electronic ballast circuit includes a directly driven high frequency inverter circuit with a series resonant output circuit coupled to a load circuit having a high intensity discharge (HID) lamp and to a drive circuit dependent upon current flow in the load circuit. A starting circuit for the high frequency inverter is coupled to a DC source and to a charge storage and isolating circuit and provides initial energization to the high frequency inverter circuit. Also, a lamp starting circuit initiates increased conductivity of the high frequency inverter circuit which causes development of energy sufficient to "fire" an HID lamp whereupon a disablement circuit essentially removes the lamp starting circuit from the operational circuitry.

Abstract: A direct drive electronic ballast circuit suitable for a fluorescent lamp load includes a high frequency oscillator inverter circuit having a tuned output circuit coupled to a load and to a drive circuit series connected to the load and dependent upon current flow therein. The high frequency oscillator inverter circuit is also coupled to a pulsed DC potential source which is shunted by a charge storage and isolating circuit energized by a feedback rectifier circuit which supplies energy whenever the potential from the pulsed DC potential source decreases below a given reference level. A relaxation type oscillator is coupled to the high frequency oscillator inverter circuit and provides a starting capability therefore.

Abstract: Electronic ballast apparatus includes a transformer having an "E"-shaped core member with a primary winding wrapped on a center leg member and coupled to a potential source and first and second secondary windings each wrapped on a first and second outer leg member of the core member and coupled to gaseous discharge lamps such that flux developed in the primary winding is differentially divided between the first and second secondary windings in inverse relation to energization of the gaseous discharge lamps.

Abstract: Addition of small amounts of nitric acid to aqueous sulfuric acid containing more than about 60% by weight of H.sub.2 SO.sub.4 inhibits corrosive attack on carbon steel with which it may come in contact.

Abstract: A highly efficient tuned oscillator ballast circuit especially suitable for a fluorescent lamp load includes an oscillator circuit coupled to a pulsed DC potential source and having a tuned output circuit coupled to a load circuit, to a drive circuit for the oscillator which is dependent upon current flow in the load circuit and to a rectifier and charge storage and isolation and applying network coupled to the pulsed DC potential source and providing energy thereto whenever the potential decreases below a given reference level. A transient compensating circuit to protect the oscillator components from initial or "start up" transients is also included.

Abstract: A high power factor conversion circuit suitable as a ballast circuit for lamps includes a full-wave rectifier coupled to an AC potential source and providing a pulsating DC potential. A high frequency inverter is coupled to a load circuit and to a feedback rectifier circuit supplying a rectified high frequency potential to an energy storage feedback circuit which provides energy in a manner to inhibit a decline in the pulsating DC potential thereby providing a substantially uniform DC potential to the high frequency inverter.