Abstract: An operating system for a sun tanning apparatus comprises an array of multiple parallel-oriented fluorescent lamps and an electronic frequency converter adapted to convert ordinary 60 Hz power line voltage into a 350 Volt/30 kHz sinusoidal voltage provided between a pair of bus conductors and suitable for directly powering each fluorescent lamp by way of a simple capacitive or inductive current-limiting reactance means. The fluorescent lamp cathodes are heated by way of individual transformers, with one transformer for each pair of lamp cathodes. Only two pairs of conductors are required for powering the complete array of mutually parallel-disposed fluorescent lamp pairs regardless of the number of lamps involved, with one pair running along the one side of the array, and the other pair running along the other side of the array. Of each pair of fluorescent lamps, one lamp is powered by way of an inductive reactance means and one lamp is powered by way of a capacitive reactance means.

Abstract: A self-oscillating inverter uses saturable transformer means in its positive feedback circuit. The saturation flux density of the magnetic material used in this saturable transformer means determines the frequency of inverter oscillation. A permanent magnet is rotatably mounted proximate to the saturable transformer means and is used for adjustably affecting the saturation flux density of the magnetic material, thereby correspondingly to adjust the frequency of oscillation: the stronger the magnetic flux provided to the magnetic material from the permanent magnet, the smaller the saturation flux density and the higher the frequency of oscillation.

Abstract: In a power-line-operated inverter-type magnetron power supply having a high-Q resonant L-C circuit series-excited by the inverter and parallel-loaded by the magnetron, subject invention provides for cost-effective means to prevent the destructive overload of the inverter and/or the L-C circuit that may occur during the brief period before the magnetron cathode becomes incandescent. In this power supply, the unfiltered pulsed DC output of a full-wave power-line-supplied rectifier means is applied to a pair of inverters: an auxiliary inverter for heating the magnetron cathode, and a main inverter for providing the main magnetron power. The auxiliary inverter starts operating immediately upon application of power from the power line, and therefore immediately starts the process of cathode heating.

Abstract: In a flyback converter, a 15 Amp N-channel power MOSFET is driven to saturation by a gate voltage derived by connecting the gate to the relatively high-magnitude (150 volt) B+ voltage by way of a resistor of relatively high resistance (about 20 kilo-Ohm). Current flowing through this resistor causes the gate capacitance (3600 pico-Farad) to charge at a rate of about 2 Volt per micro-second. Since the forward transconductance of the MOSFET is 6 mhos or more, a situation has been established where the MOSFET is effectively fully switched ON as long as the MOSFET's drain current does not rise at a rate higher than about 12 Amp per micro-second.Eventually, the magnitude of the gate voltage reaches a predetermined maximum level (about 20 Volt), at which point a threshold device, which is connected between gate and source, breaks down and rapidly discharges the base capacitance, thereby rapidly switching the MOSFET into a non-conducting state.

Abstract: An electronic ballast powers fluorescent lamps in a lighting fixture with a current of magnitude related to the frequency of the ballast output voltage. The ballast comprises self-oscillating inverter means wherein the frequency of oscillation can be influenced by receipt of a control signal at a control input connected in circuit with the inverter's positive feedback circuit. The ballast also comprises optical sensor means so positioned and constituted as to sense the light level within the lighting fixture and to provide a control signal commensurate with the light level. This control signal is then applied to the control input in such manner as to regulate the inverter frequency as a function of the light level, thereby correspondingly to regulate the magnitude of the current fed to the fluorescent lamps.

Abstract: From a central point, both telephone signals and Class-2 high frequency electric power are transmitted by way of a common transmission cable to the location of a telephone apparatus; thereby to provide at that location, not only telephone signals, but also a limited amount of electric power useful for various things, such as task lighting. At the central point there is provided a non-interruptible source of electric energy, namely a frequency-converting power supply connected both with an ordinary 120 Volt/60HZ power line as well as with a storage battery. This power supply provides output of Class-2 high frequency voltage. Together with the telephone signals, this Class-2 voltage is transmitted by way of an ordinary telephone installation cable to the location of a telephone apparatus.

Abstract: In an inverter-type fluorescent lamp ballast, the inverter is powered from an ordinary electric utility power line by way of a rectifier means providing to the inverter a DC voltage having magnitude variations of about plus/minus 30% occurring at twice the frequency of the power line voltage. The inverter's output is a squarewave voltage of frequency averaging about 30 kHz and with amplitude modulations of about plus/minus 30%; which squarewave voltage is applied to a series-tuned L-C circuit. The fluorescent lamp is connected in parallel with the tank capacitor of this L-C circuit, thereby being provided with a current of magnitude proportional to the magnitude of the squarewave voltage. Within a significant range, the magnitude of the lamp current is a sensitive function of the frequency of the squarewave voltage; which frequency is modulated in such a way as to compensate for the variations in lamp current that would otherwise result from the amplitude modulation on the squarewave voltage.

Abstract: A fluorescent lamp is mounted on an ordinary Edison-type screw-base; which screw-base contains a frequency-converting electronic ballast. The combined lamp-ballast-assembly is adapted to be used in an ordinary screw-in lamp socket powered from ordinary 120 Volt/60 Hz power line voltage. The frequency-converting ballast within the screw-base converts the 120 Volt/60 Hz power line voltage to a high-frequency (20-30 kHz) substantially sinusoidal current, which is then used for powering the compact fluorescent lamp.

Abstract: An inverter-type ballast has built-in differential current transformer operative to sense any substantive difference in the currents flowing from each of its two output terminals. If a substantive difference exists for more than just a brief period, a trigger circuit operates to disable the inverter, thereby to remove voltage from the output terminals.

Abstract: In a self-oscillating inverter-type fluorescent lamp ballast, the inverter's output is a squarewave voltage of frequency controllable about 30 kHz. The squarewave voltage is applied across a series-connected high-Q L-C circuit. The fluorescent lamp is connected in parallel with the tank capacitor of this L-C circuit. Before the lamp ignites, the magnitude of the voltage developing across the tank capacitor is a sensitive function of the frequency of the squarewave voltage and is controlled to a suitable level by correspondingly controlling the frequency of the squarewave voltage to be higher than the natural resonance frequency of the unloaded L-C circuit. After the lamp has ignited, the magnitude of the lamp current is a sensitive function of the frequency of the squarewave voltage and is controlled to a suitable level by correspondingly controlling the frequency of the squarewave voltage.

Abstract: An office wall partition includes a central electronic high-frequency power supply as well as a main fluorescent lamp. The power supply is removably comprised within the partition; and the main fluorescent lamp is inserted into and held by a pair of sockets connected with the power supply by way of a high frequency ballast and mounted within a long narrow compartment on top of the partition. The width of this compartment is only about 2.5", which is about the same as the thickness of a standard office partition; and its length is nearly 6', which is nearly the same as the width of a standard office partition. The fluoresent lamp emits the light upward in the form of a beam of approximately 120 degree spread, thereby providing for glare-free ambient illumination reflected off the ceiling. Power track means and receptacle means mounted on the partition are connected with the power supply and provide for the cost-effective operation of various incandescent and/or fluorescent task lighting modules.

Abstract: A self-contained electronic wall switch actuator can easily be mounted directly onto the outside of the face plate of an ordinary wall switch. When so mounted, the actuator engages the wall switch's actuating lever and permits the automatic actuation of the wall switch by way of simple touch action: (i) by lightly pressing a Bypass Key, the wall switch is caused to reverse its state from ON to OFF, or from OFF to ON, whichever is appropriate; (ii) by lightly pressing a Delay Key, the wall switch is caused to enter its ON-state and to remain there for a presetable first period of time; and (iii) by lightly pressing a Cycle Key, the wall switch will, starting right then and repeatedly every 24 hours thereafter, enter its ON-state for a presetable second period of time.The actuator comprises a small battery, a miniature electric motor with a gear/linkage mechanism operable to engage with and to move the wall switch's actuating lever between its OFF and ON positions, and a quartz-clock-based programming means.

Abstract: In a power-line-operated high-frequency electronic fluorescent lamp ballast, an inverter is powered from a DC supply voltage having a substantial amount of 120 Hz ripple. The fluorescent lamp is connected with the inverter's squarewave output voltage by way of a series-resonant L-C circuit. The amount of power supplied by the inverter to the series-resonant L-C circuit and/or to the fluorescent lamp at any given moment depends on three significant factors: (i) the instantaneous magnitude of the DC supply voltage, (ii) the instantaneous frequency of the inverter's squarewave output voltage, and (iii) the instantaneous operational characteristics of the fluorescent lamp. Arrangements are provided whereby the instantaneous inverter frequency is automatically adjusted so as to prevent inverter overload in case the fluorescent lamp is non-present or inoperative.

Abstract: A frequency, voltage and waveshape converter is placed between the power line and the power input terminals of a load means (such as a fluorescent lighting system wherein the fluorescent lamps are operated by way of ordinary magnetic ballasts designed to be powered on regular 60 Hz power line voltage). The converter is controllably operable to provide to the power input terminals of the load means an AC voltage of frequency, magnitude and/or waveshape different from those of the power line voltage, thereby to permit effective control of the current supplied to the load means. In case of the load means being a fluorescent lighting system, the frequency of the AC voltage is adjustable over the range of 50-500 Hz, thereby providing for a very wide range of light output control.

Abstract: For the magnetron in a microwave oven, a full-bridge inverter power supply comprises two pairs of switching transistors and is conditionally operable to self-oscillate in either of two modes: a first mode wherein one of the two pairs of switching transistors self-oscillates in manner of a half-bridge inverter and powers the magnetron's thermionic cathode, and a second mode wherein both pairs of transistors self-oscillate in manner of a full-bridge inverter and then provide the magnetron's anode power as well as its cathode heating power. The first mode gets initiated immediately upon applying power to the power supply, but the second mode does not get initiated until about 5 seconds after the initiation of the first mode. That way, the cathode will have become fully thermionic prior to applying anode power to the magnetron.

Abstract: An AC/DC converter comprises a half-bridge electronic self-oscillating inverter powered from the non-filtered full-wave-rectified 120 Volt/60 Hz power line voltage, and its resulting amplitude-modulted 30 kHz output voltage is applied to a series-resonant L-C circuit. The 30 kHz voltage developing across the tank capacitor of this L-C circuit is rectified and applied as DC to an energy-storing capacitor, from which the AC/DC converter's output is supplied. Trigger pulses are provided to trigger the inverter into self-oscillation at the beginning of each pulse of DC voltage provided by the unfiltered rectified power line voltage. As soon as the magnitude of the DC voltage across the energy-storing capacitor exceeds a first level, the trigger pulses cease to be provided. As soon as the magnitude of the DC voltage on the energy-storing capacitor falls below a second level, the trigger pulses are again provided.

Abstract: In a power-line-operated high-frequency electronic fluorescent lamp ballast, an inverter is powered from a DC supply voltage having a substantial amount of 120 Hz ripple. The fluorescent lamp is connected with the inverter's squarewave output voltage by way of a series-resonant L-C circuit. The amount of power supplied to the fluorescent lamp at any given moment depends on two significant factors: (i) the instantaneous magnitude of the DC supply voltage, and (ii) the instantaneous frequency of the inverter's squarewave output voltage. Arrangements are provided whereby the instantaneous inverter frequency is automatically adjusted over the duration of the 120 Hz ripple cycle such as to maintain the power supplied to the lamp substantially constant during this ripple cycle. As a result, in spite of a relatively large amount of ripple, the lamp current crest factor is maintained relatively low and substantially constant.

Abstract: A plug-in timer has a set of input terminals and a set of output terminals as well as a contactor operable to make and/or break electrical connection between these sets of terminals in accordance with a pre-setable 24 hour program. The timer is powered from a small built-in battery, and comprises its own quartz clock and programming-and-control means. The contactor is actuated by a miniature DC motor through a gear and cam arrangement. The operation of the DC motor is controlled by the programming-and-control means, which provides power from the battery to the motor in accordance with a pre-set program; which pre-set program may be modified at any time by way of a keyboard and a numeric display means.The contactor operates by way of hard metal contacts and very little power dissipation occurs within the timer. The timer can be plugged into an ordinary household electrical receptacle, and a load may be plugged into the timer.

Abstract: Subject invention relates to an inverter-type electronic fluorescent lamp ballast wherein a series-resonant LC circuit connected across the inverter's output is used for matching the inverter's operating characteristics to those of the fluorescent lamp--the fluorescent lamp being connected in parallel with the tank-capacitor of this LC circuit. In particular, the invention relates to the use of a Varistor coupled in parallel with this tank-capacitor, thereby limiting the voltage developed thereacross to a magnitude suitable for proper lamp starting. Moreover, by providing for means whereby the inverter shuts itself off in case current flows through this Varistor for more than about one second or so (which is the maximum length of time that it should normally take for a fluorescent lamp to start), inverter as well as Varistor overload protection is obtained.

Abstract: Subject invention relates to an inverter-type electronic fluorescent lamp ballast wherein a series-resonant LC circuit connected across the inverter's output is used for matching the inverter's operating characteristics to those of the fluorescent lamp--the fluorescent lamp being connected in parallel with the tank-capacitor of this LC circuit.More particularly, the invention relates to the use of a Varistor coupled in parallel with this tank-capacitor, thereby limiting the voltage developed thereacross to a magnitude suitable for proper lamp starting. Moreover, by providing for means whereby the inverter shuts itself off in case current flows through this Varistor for a longer time than it should take for a fluorescent lamp to start, inverter overload protection is obtained. Without such overload protection the inverter would selfdestruct in case the fluorescent lamp failed to start or if it were removed from the circuit.