Abstract: A power source for operating gas discharge lamps and other loads at high frequency, typically utilizing a 120 volt ac source rectified to provide a 150 volt dc input and providing a 20,000 hertz output. An inverter with current feedback in place of the conventional voltage feedback providing voltage turn off and voltage turn on in less time and providing increased base current during the conduction time for reducing the voltage-current product and heat generated in the inverter. Voltage limiting and current limiting features are provided for the basic circuit. Inverter circuits with two transistors for increased loads are also provided.

Abstract: In the present magnetron operating circuit for generating microwave energy, the circuit components of the filter, the transformer and the rectifier are arranged within a shielded housing, in the same manner as the cathode input portion of a magnetron tube. A feed-through capacitor of the filter is arranged in the low voltage line of the transformer and secured to the wall of the housing to prevent undesired radiation. A coil with a ferrite core of the filter is preferably connected to the filament lead of the magnetron tube.

Abstract: It is the purpose of the present discharge lamp lighting system to provide reignition energy to a discharge lamp in each half cycle of the a.c. power source. The discharge lamp is connected to a conventional a.c. power source through ballast means and an oscillation booster circuit, which provides an intermittent oscillation output for the reignition operation of the discharge lamp. The operation period of the intermittent oscillation output is so controlled that the reignition operation period is included in each half cycle of the discharge lamp current. The lamp voltage and source voltage are established to agree as much as possible with each other for minimizing the terminal voltage of the ballast means, whereby a compact and economical device with a small inductance ballast means is achieved.

Abstract: A fluorescent lamp lighting device comprises a d.c. power source, a transistor, a transformer and a fluorescent lamp. The d.c. power source is connected in series with the primary winding of the transformer between a first electrode and a second electrode of the transistor. The fluorescent lamp has one filament connected to one end of a first secondary winding of the transformer. A second secondary winding of the transformer is connected between the other end of the first secondary winding of the transformer and the junction of the d.c. power source and the primary winding of the transformer. The fluorescent lamp has the other filament connected between the junction of the first secondary winding of the transformer and the second secondary winding and a third electrode of the transistor.

Abstract: A high frequency power supply with inductive coupling and a SCR starter to light two fluorescent lamps is described. It supplies high frequency square waves to the fluorescent lamp for improved light output, efficiency and stability of operation. The rectified line voltage from a full wave rectifier is fed via a SCR starter to two transistors that form an inverter circuit. The inverter circuit is coupled to a ferrite core autotransformer. The secondary windings of the autotransformer are used to heat the filaments of the electrodes of the fluorescent lamp, and to form a reactive coupling along with inductors for stabilizing the arc discharge of the fluorescent lamp.

Abstract: An improved method of and apparatus for operating an electric discharge lamp which includes a controlled semiconductor switch connected in shunt with the lamp. By means of the semiconductor switch, the discharge lamp receives, when in operation, a plurality of voltage peaks, during every second half cycle of the AC supply voltage.

Abstract: A circuit for operating an electric discharge lamp wherein a change in the mode of operation of the circuit is effected in response to a change of phase of a voltage or current in the circuit which occurs during operation e.g. when the lamp strikes or as the lamp runs up to full current.

Abstract: A circuit employing an oscillator having a feedback loop for supplying operating current at a frequency in the range 20-25 kilohertz to a pair of fluorescent lamps connected in series. The heater filament of the first lamp is made a series element in the feedback loop of the oscillator, so that removal of that lamp disables the oscillator. Switching means is provided to bypass the open socket terminals of the second lamp when it is removed from its sockets, permitting power to continue to be supplied to the first lamp.

Abstract: A method and apparatus of lighting a cold cathode electric gas discharge lamp in which the lamp is connected across the secondary winding of a voltage step-up transformer, and the primary winding of the transformer is energized with a chopped D.C. voltage having a frequency of at least 12 kHz and a voltage which provides an output voltage from the secondary winding having an R.M.S. value no greater than 700 volts.

Abstract: A ballast circuit for a discharge lamp uses simply a capacitor in series with a relatively small inductor the capacitative reactance being between 24 and 55 times the inductive reactance. At these values the third harmonic distortion is unexpectedly low, while the crest factor (ratio of peak to r.m.s. current) is still within acceptance values. Because the inductor is small the efficiency of the circuit is high, and its cost and weight reduced. The capacitance/inductance ratio can be equated to the ratio of the frequency of the tuned circuit to the supply frequency, and on this basis the preferred range is defined by 5 to 71/2 times supply frequency.

Abstract: A voltage producing device comprises a circuit in which an AC power source, a coil and a first capacitor connected in series. A unidirectional triode semiconductor switching element is connected across both terminals of the capacitor, a voltage limiting semiconductor element is connected to a gate electrode of the switching element, and a charging-and-discharging circuit including a second capacitor is connected to a cathode of the switching element.

Abstract: In the system disclosed, a transformer connected to an alternating power source establishes a continuous alternating output voltage which is connected directly across a gas discharge lamp to apply the voltage continuously across the lamp. The transformer output voltage is set within a range which includes a condition that causes the lamp to exhibit a positive impedance value when the lamp is discharging. The transformer and the source together exhibit an impedance substantially less than the impedance value of the discharging lamp.

Abstract: In a microwave energy generating system, a combination of a magnetron which generates microwave energy and an inverter which converts DC voltage to high frequency AC voltage are employed. The magnetron includes a heater-cathode and an anode. The inverter includes a transformer having a gapped ferrite core, a center tapped primary winding which divides the primary into two portions, and at least a first high voltage secondary winding and a second low voltage secondary winding for the magnetron heater, and means for switching current through each winding half alternately at a periodic high frequency rate, substantially above 60 Hz., to produce a high frequency magnetic field in said ferrite core, and means, including inductor means, are provided for providing DC current into said primary winding at said center tap.

Abstract: A fluorescent lamp installation for very high intensity illumination uses standard rapid start filament type lamps with standard ballast remote from the lamp pairs to reduce cooling requirements. The heavy wiring harnesses previously required of six leads between each ballast and a lamp pair are reduced to one with a common lead for all the lamp pairs.

Abstract: A power supply circuit for a microwave oven which includes a magnetron, a transformer, a plural capacitor, and a current rectifier. The power supply circuit is particularly adapted to provide constant power output from the magnetron using either a 50Hz or 60Hz input power by selecting an appropriate one of said plural capacitances.

Abstract: A television receiver includes a switched-mode power supply driven by the horizontal oscillator and driver section of the television receiver. An on/off switch for the receiver is connected to the switched-mode power supply to vary its output according to the setting of the on/off switch. This output, when the switch is "on", is used to supply full operating potential to the cathode ray tube filaments and operating potential for some of the portions of the television receiver. When the on/off switch is in its "off" position, it operates to cause the power supply to supply reduced or standby potentials to those same portions of the receiver and to the cathode ray tube filaments. At the same time, other portions of the receiver are turned off and on in the normal fashion.