Abstract: The system of the present invention deals with an electronically controlled, low cost RFID Interrogator/Induction Heating System which does not require a separate interrogator, rather utilizing components within the system for purposes of interrogation.

Abstract: A high frequency battery charger includes a converter, drive logic, and control logic. The converter transforms a DC voltage into a high frequency AC voltage. The drive logic controls a conversion of the high frequency AC voltage through a train of pulses. The control logic adjusts the output of the converter to maximize a charging cycle of a battery. The method of transforming an AC input into a direct current output used to charge a rechargeable battery includes transforming an AC input into a first DC output; transforming the first DC output into a high frequency AC output; transforming the high frequency AC output into a second DC output; and passing a charging current to an external load when the load is correctly connected to an output.

Abstract: Apparatus for detecting certain load fault conditions of gaseous luminous tube loads connected to high voltage, high frequency power supplies including open-circuit, broken tube and other balanced load fault conditions. The detector includes a filter for emphasizing the harmonic content of the power supply output, an attenuator, a comparator or other detector/threshold device, and a delay circuit. A power supply shut-down switch may be included or the present fault detector may be interconnected to shut-down switch of a conventional ground fault interrupter. In one embodiment the filter and attenuator and, in another, the filter, attenuator, and delay circuit employ common components and may include a filter/attenuator capacitor defined by placement of metalization on the high frequency power supply transformer adjacent a high voltage output lead.

Abstract: A modular neon sign system comprising two or more independent neon or similar luminous tube segments. One or more of the luminous segments are arranged in generally parallel configuration across the remaining tube segments and each such parallel segment includes a series capacitive ballasting element to selectively control the current through the respective segment. Receptacles may be provided to facilitate the attachment of the parallel segments thereby forming detachable neon modules. The capacitive ballasting element is preferably a ceramic button-like disc that may be connected to an end of the parallel neon module or inserted into the receptacle. In one embodiment the several parallel segments are connected to a reduced tension constant voltage power supply. In a second erabodiment, a constant current power supply is continuously interconnected to one or more neon luminous tubes that define a fixed portion of the sign with the parallel segment(s) or module(s) being connected across said fixed portion.

Abstract: A high frequency power supply for neon and mercury luminous tubes including means for simultaneously suppressing bubbles formed in neon tubes and for minimizing migration of mercury commonly associated with the use of solid-state luminous tube power supplies.

Abstract: A low frequency parasitic oscillation suppressor for series, current-fed high frequency luminous tube power supplies. The suppressor incorporates a transformer, the primary of which serves as the conventional series input choke. A parasitic damping resistor and diode are connected in series with the transformer secondary and this series combination is, in turn, connected across the DC supply source for the oscillator. The transformer turns-ratio is selected such that no current flows through the series secondary under normal operating conditions. Upon the generation of a low frequency parasitic oscillation, a current is caused to flow through the secondary including the parasitic damping resistor thereby dampening the parasitic oscillation while maintaining normal high frequency operation.

Abstract: Apparatus for dimming neon tubes and signs in which certain problems associated with high dimming levels (lowered illumination intensities), namely, of tube non-excitation and non-uniform illumination, are eliminated. The apparatus includes a generator for creating pulse groups, which groups consist of one or more high frequency, full-amplitude pulses and a modulator for selectively controlling the repetition rate of the pulse group and/or the number of pulses forming each group. The apparatus further includes ground fault interruption circuitry that is immune from the false triggering occasioned by the low pulse group repetition rate which in turn results in the repeated de-ionization/re-ionization of the neon gas. The ground fault interruption circuitry includes a detector for establishing the initiation of a pulse group and an inhibitor to preclude ground fault interruption during periods of gas re-ionization following the commencement of each pulse group.

Abstract: A high frequency power supply for neon and mercury luminous tubes including means for simultaneously suppressing bubbles formed in neon tubes and for minimizing migration of mercury commonly associated with the use of solid-state luminous tube power supplies.

Abstract: A high frequency PWM power supply for luminous tubes including a low power constant frequency, uniform pulse width generator which charges the intrinsic input capacitance of an insulated junction power FET thereby switching a source of DC voltage across the primary of a high voltage transformer. A current sense resistor and load current compensator discharge the FET gate capacitance upon attaining a predetermined average luminous tube load current. The secondary power supply output includes a series capacitance to minimize tube end discoloration particularly prevalent in mercury luminous tubes. A ground fault detector employing the intrinsic secondary capacitance and transformer core with a dual-peak detector thereby providing enhanced accuracy and ground fault reliability.

Abstract: A high efficiency, low cost solid state power supply for gas discharge or other devices including a resonant oscillator having a high voltage transistor and a switching circuit connected to the high voltage transistor adapted to rapidly turn-off such transistor. The switching circuit including transistors interposed to interrupt the emitter current path of the high voltage transistor to force rapid cut-off thereof. The switching circuit coupled to the oscillator output tank capacitance which functions additionally as a differentiator to actuate the switching circuit.