Abstract: The input energy to a gas discharge lamp is controlled over a given range to obtain output light regulation in a controlled fashion for different kinds of gas discharge lamps, including fluorescent lamps, high intensity discharge lamps and others associated with any type ballast, including conventional non-dimming type ballasts. A suitable circuit switches each half wave of an input a-c wave form from some instantaneous value greater than zero to a substantially zero value and then back to a value greater than zero one or more times in each half cycle. The time duration of the substantially zero energy interval is varied to vary the total energy applied to the gas discharge lamps. In a preferred embodiment, a first high speed electronic switch is connected in series with the a-c source and lamp ballast and a high speed electronic shunt switch is connected across the a-c line and ballast input. The series switch is opened to produce the zero energy interval.

Abstract: A two-wire ballast arrangement for fluorescent lamp dimming is disclosed in which a modified transformer utilizing the natural leakage inductance associated with ballast transformers is used to achieve full-range fluorescent tube dimming at substantially constant filament heating voltage. Additional auxiliary secondary windings are disposed in predetermined spaced relationship to the primary winding and the main secondary winding to create a "tapping" effect in the magnetic flux. The mutual leakage inductances of the auxiliary secondaries in relation to the primary and the main secondary is utilized in a manner such that as the voltage is decreased to the primary, the voltage of the auxiliary secondary windings remains substantially constant to hold the filament heating voltage substantially constant. Embodiments are disclosed for use either with conventional 50/60 Hz or at high frequency, i.e. above 400 Hz.

Abstract: A method for starting and operating a preheat type fluorescent lamp includes a source of alternating current, a fluorescent lamp having a low impedance starting mode wherein current passes through one or more starting filaments and a high impedance operating mode wherein current passes through the length of the lamp, a starting switch directing current through the starting filaments in the lamp starting mode, and an inductor ballast having a magnetically permeable core operating in a saturated condition when the lamp is in the low impedance starting mode and in a non-saturated condition when the lamp is in the high impedance operating mode.

Abstract: A variable frequency AC power source drives a gas discharge lamp which is connected in parallel with the capacitance of a series resonant circuit. The polarity of the voltage applied to the resonant circuit is commutated at such times as the rate-of-change of current flow in the resonant circuit is below an adjustable threshold value. The setting of a threshold adjusting circuit determines the brightness of the lamp. The polarity is also commutated at such times as the current flow from the source reaches a predetermined level. Lamp current is thus independently and variably controlled in the variable power mode.

Abstract: A liquid level presence detection circuit includes a selectively gatable TRIAC serially connected with a load and triggered into conduction by twin sensitive-gate SCR's connected anode-to-cathode with the gates of the SCR's connected to voltage divider circuits which provide gating current to the SCR's in response to the presence of a conductive liquid bridging the two spaced apart contacts of a liquid presence detecting probe. The circuit is used in wet-niche type lamp assemblies that provide underwater illumination in swimming pools and the like and in which cooling is effected by the surrounding liquid. The detection circuit advantageously interrupts the flow of electrical energy to the lamp when the level of surrounding liquid falls below a predetermined level to prevent over-temperature operation of the lamp and consequent damage thereto and resumes the flow of electrical energy to the lamp when the level of the surrounding liquid increases to a safe level to permit adequate cooling thereof.

Abstract: A light dimmer switch is shown that appears as an ordinary snap switch, but will handle high wattage loads. A controller unit is mounted in a switch box and a remote unit which includes a load switching triac is remotely mounted on a heat sink. Current flowing through the triac to the load is varied by the controller unit. Filtering networks and/or shielding reduce radiated noise along lead lines between the remote unit and the controller unit, plus the filtering prevents noise from being conducted internally along the lead lines. Heat conducted along the lead lines from the remote unit is reduced to more than acceptable levels by connecting the lead lines through a terminal to a thin electrically insulating, thermally conductive strip. In turn, the insulating strip is fixed to the heat sink to transmit heat received from the lead lines to the heat sink.

Abstract: For the purpose of controlling the electrical energy fed to an electrical gas-discharge lamp (20), without an incandescent cathode, as a function of a d.c. control voltage (U.sub.S), there is a circuit arrangement (IC1, R3-R11, C4-C6, D-1), by means of which the ignition timing or angle of a triac (TR1) may be varied within each alternating-voltage half-wave. In order to prevent the lamp (20) from being completely extinguished unintentionally, when adjusted to minimal brightness, an additional circuit arrangement (30, 42, R12-R20, C7, D3, T1) is provided, ensuring a given minimal intensity of the current, flowing through said lamp (20), regardless of the level of said d.c. control voltage (U.sub.S). Said additional circuit arrangement comprises a current transformer (30) and a rectifier arrangement (42) for producing a regulating voltage (U.sub.R) dependent upon the intensity of the lamp current which controls an electronically variable resistance (T1).

Abstract: A device and a method for reducing power consumption and correspondingly reducing lumen output of a phosphor excitable lamp, such as a fluorescent lamp, connected to a source of power for operation of the same, without any appreciable loss of operating efficiency. A capacitive element is electrically connectable to one terminal of the phosphor excitable lamp and is effectively electrically interposed between the lamp and the source of power in a series connection. The capacitive element is selected with a capacitive value so that the lumen output is reduced but with substantially uniform lumen output at the reduced level and the power consumption is reduced without substantially changing the voltage to the lamp and without any appreciable effects on the efficiency of operation of the lamp or the source of power.

Abstract: A power saving circuit for a gaseous discharge lamp includes a power circuit and a control circuit. The power circuit is connectable to an AC power supply and to at least one lamp and has a bilateral current conducting power switch with control electrode means. The control circuit has a control switch with control electrode means, and timing means operable to apply a signal to the control electrode means of the control switch to render the control switch conducting at a predetermined time during each half cycle of the AC power supply, the control switch conducting current until zero crossover at the end of each half cycle. Opto-coupler means are associated with the control switch on the one hand and with the control electrode means of the power switch on the other hand to cause actuation of the control electrode means of the power switch and subsequent current conduction by the power switch when the control switch is conducting.

Abstract: There is disclosed herein a method and apparatus for controlling the power dissipation in a load particularly suitable for use as a dimmer control for lighting circuits. Selected half cycles are applied to a load, such as an incandescent lamp. The number and sequence of the half cycles applied to the load are selected by logic circuitry which, according to the setting of a dimmer control, determines how many complete half cycles out of the total available to apply to the load. Zero crossing switching is used.

Abstract: A fluorescent lamp dimming circuit is disclosed for DC fluorescent lighting circuits of the type using a battery voltage source and an inverter. The dimming circuit comprises an electronic switch (24) connected between the battery (18) and the inverter (16) and an oscillator (26) is provided to periodically actuate the electronic switch to reduce the on-time of the lamp current. A timer (30) is connected with the oscillator (26) to disable the dimming circuit for a preset time interval after the lamp has been turned on by an on/off switch (20). Thus, the lamp is started at full intensity upon each start-up and after the time delay the dimmer circuit is effective to reduce the intensity.

Abstract: A control circuit and method is provided to automatically cut out a dimmer circuit from a high intensity light source until the light source has first been triggered and turned on at a high intensity level with the required high voltage. After an initial high illumination occurs a dimmer control circuit is electronically cut into the light circuit and a dimmer control knob, connected with a potentiometer, may then be used to raise or lower the illumination of the high intensity lamp. Thus, the high intensity lamp will be turned on regardless of the position of the dimmer control. Without the control circuit, the high intensity lamp would not trigger if the control knob was at a low intensity setting.

Abstract: A dimming circuit for operating a fluorescent lamp in an incandescent-to-fluorescent adapter at two selectable current levels. The circuit includes a choke which is series connected between the center contact of a three-contact incandescent base and one of the lamp filament coils, and a capacitor connected between the ring contact and center contact of the base. A bleeder resistor of the PTC type is connected across the capacitor. For use with an incandescent lamp fixture having a four-position, three-way switch, the circuit further includes a current limiting discharge resistor connected in series with the capacitor.

Abstract: A means for regulating the power of a fluorescent tube in a vehicle supplied by a DC source by providing the control circuit of an oscillator transistor of an inverter with an adjustable RC circuit. Even very much dimmed tubes can be lighted with the use of a switch by-passing the RC circuit.

Abstract: Solenoidal electric field lamps are effectively dimmed with no loss in lamp efficiency by powering the lamps with high frequency current pulses and periodically interrupting the current pulses in a time ratio fashion in order to reduce the average power being supplied to the lamp. The lamp may be dimmed from 100 to 0 percent of full power in an efficient manner as long as the pulse interruption period is less than the plasma deionization time of the lamp.

Abstract: A light indicating monitoring system includes a plurality of light emitting diodes (LED's) having a common ground connected to a phase controlled silicon controlled rectifier (SCR) circuit. The SCR circuit limits conduction of rectified AC energy through the LED's and through corresponding resistors connected in series with the LED's for limiting the current through the LED's. The SCR circuit thereby provides for operating low DC voltage LED's from a high AC voltage source with a minimum of power and heat generation in the current limiting resistors.

Abstract: An illumination control system for gas discharge lamps which can be dimmed is provided in which a central inverter produces a sinusoidal output voltage at about 23 kHz. The amplitude of the inverter output is adjustable to dim the lamps. A transmission line consisting of spaced wires having respective thick insulation sheaths distributes the high frequency power to remotely located assemblies of ballasts and lamps. The ballasts consist of passive linear components. A high power factor rectifier network is disclosed for providing a d-c input to the inverter from the 50/60 Hz mains. The inverter circuit is provided with novel controls for gradual start-up and turn-off and is protected against load fault currents and internal fault currents. Automatic and manual resets are provided for internal fault current and load fault current, respectively. The basic inverter circuit consists of two alternately conducting controllably conductive power switching devices.

Abstract: An illumination control system for gas discharge lamps which can be dimmed is provided in which a central inverter produces an output voltage at a high frequency which can be about 23 kHz. The amplitude of the inverter output is adjustable to dim the lamps. A transmission line consisting of spaced wires having respective thick insulation sheaths distributes the high frequency power to remotely located assemblies of ballasts and lamps. The ballasts consist of passive linear components. A high power factor rectifier network is disclosed for providing a d-c input to the inverter from the 50/60 Hz mains.

Abstract: An illumination control system for gas discharge lamps which can be dimmed is provided in which a central inverter produces sinusoidal output voltage at about 23 kHz. The amplitude of the inverter output is adjustable to dim the lamps. A transmission line consisting of spaced wires having respective thick insulation sheaths distributes the high frequency power to remotely located assemblies of ballasts and lamps. A high power factor rectifier network is disclosed for providing a d-c input to the inverter from the 50/60 Hz mains. Several ballasts are disclosed, which consist principally of circuits using passive linear components. Some of the ballasts disclosed are conjugate ballasts which are those made of complex conjugate impedances which resonate with or near the input power frequency. Some ballasts disclosed are non-linear when the lamp is out in order to limit the open circuit voltage. The ballasts disclosed all have the following characteristics:(a) good power factor (above 0.

Abstract: A dimmer circuit for a high intensity, gaseous discharge lamp having a ballast with a reactive portion, the current bypass or partial bypass of which determines the brightness of the lamp, the bypass being controlled by gated bypass means, preferably in the form of a triac, driven by the photodrive element of an optocoupler, the light emitting diode element of the optocoupler receiving pulses and actuating the photodrive element for passing a gate trigger signal to the gated bypass means.

Abstract: A dimmer circuit for providing gate signal to a gated semiconductor connected for at least partial bypass operation of a ballast element of an HID lamp, the gate signal being derived from a high frequency voltage in a predetermined range. The high frequency voltage is separated from other frequencies and converted to a voltage proportional to the frequency. The voltage is then converted to a pulse within the timed operational limits of the line voltage for gating the semiconductor, and hence producing a brightness of the lamp between predetermined limits of full dim to full bright. Preferably, the high frequency voltage carrying the control information arrives superimposed on the line voltage to thereby avoid having to use a separate set of leads to the lamp to provide light level control signalling.

Abstract: A highly energy efficient lighting system for fluorescent lamps is provided comprising a blocking oscillator having a dimmer for reducing power consumption. In one embodiment a built in power supply transformer and a battery charger provides for AC operation, portability, and emergency lighting situations. The fluorescent lamp is excited in an energy efficient manner by a high frequency blocking oscillator circuit and the dimmer permits reduction of light output reducing power drain even further thereby enabling longer battery operation, reduced size, and reduced operation costs. Also the dimming feature is important in establishing a proper mood simulating candlelight, etc.

Abstract: In one form of the present preferred embodiment of the present invention it relates to a three-position feed-thru electric line or wire cord piercing switching combination of the rotary type which at least saves electric energy by use of a half-wave diode rectifying means. The electric energy saving, three-position, combination switch having one "off" and two electrical passing switching positions.

Abstract: A two-wire ballast arrangement is disclosed for fluorescent tubes having first and second terminals for supplying variable power to dim the fluorescent tube, a choke coil connected between the first terminal and the fluorescent tube and a filament transformer having a primary connected between the second terminal and a tap on the choke coil, the tap being selected to supply substantially constant voltage to the primary winding, the transformer having secondary windings to supply filament voltage to the fluorescent tube.

Abstract: A lamp system is provided wherein a high radiation intensity metal vapor electric discharge lamp is matched with a controllable regulating transformer which is characterized by having a sufficiently high open circuit voltage for striking an arc across the lamp and by having loose coupling between primary and secondary windings along with high impedance of the secondary winding sufficient for limiting an initially high starting current through the lamp to a value whereby, as the lamp warms up on power from the transformer, the lamp current decreases and the voltage across the lamp increases, allowing the lamp to reach a high radiation intensity level of operation, the system further being one in which the transformer is controlled by having controllable core structure to select a different intensity level of operation of the lamp.

Abstract: An electronic circuit for de-energizing a lamp or other load after a predetermined period of time uses a gate controlled switch, e.g., thyristor, connected between the load and a source of A.C. voltage. The gate of the thyristor receives control current through a capacitor across which is connected a manual switch. In order to maintain the lamp energized, the switch is closed, bypassing the capacitor, so that uninterrupted gate current flows into the thyristor gate terminal to maintain the thyristor on. The delayed turn-off function is provided by opening the manual switch, whereby the capacitor in the thyristor gate charges up at a rate determined by an RC time constant. The charge build-up on the capacitor decreases the magnitude of gate current until the thyristor turns off due to gate current starvation. Several different embodiments of the circuit are disclosed.

Abstract: A power reducer for a rapid start fluorescent lamp includes a time delay circuit that discontinues heater current to the lamp cathode after a predetermined time interval and places, at the same time, a current-reducing capacitor in series with the lamp.

Abstract: A circuit for providing remote control at a plurality of locations for a lighting system, such control functions including on/off, dimming intensity and rate of dimming. Visual indication of take control is also provided.

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: An improved electric energy saving incandescent lamp socket combination having in one embodiment a two-position electric "off-on" switching means, and in another embodiment having a four-position electric "off", low, medium and high switching means for a 1-way and a 3-way incandescent lamp respectively. The lamp socket houses therein a subcombination means that comprises a conventional two-position switching means having at least one single throw "off-on" electrical switching position and a half-wave, electric rectifying, diode which is electrically short-circuitingly connected to any two of generally three electrical terminals which project from at least one surface portion of the conventional two-position switching means.

Abstract: Energy is saved in lighting lamps by pulse operation at periodic duty cycles of less than 100% on time with little effect on apparent brightness when viewed by the normal human eye because of the quality of retention of a peak flask for a finite time. At periodic frequencies above about fourteen cycles the lamps appear to be continuously energized with little flicker.

Abstract: To solve a flicker problem in a discharge lamp dimming system which results from non-synchronous high frequency, substantially sinusoidal perturbation signals imposed upon the AC line, the intensity control section of the circuit is modified. In one form of the preferred embodiment, a secondary winding of the input transformer is spaced apart from the primary winding thereof to increase the leakage reactance of the secondary winding and to decrease the capacitive coupling between windings. A capacitance of suitable value is connected across the output of the secondary winding thereby allowing the combination to serve as a low pass filter to block the line perturbation signals. In another form of the preferred embodiment, a differentiator-limiter-integrator network is included in circuit to provide a non-perturbed zero-crossing for the firing circuit, ie, the intensity controller, thereby to eliminate flicker.

Abstract: Disclosed is a lamp-dimmer which employs a novel circuit to provide a digitally selected and phase-shifted trigger-impulse for firing a triac.

Abstract: A controlled dimmer lighting system suitable for television studios, remote television pickups and stage lighting employs small, solid state dimmer circuits of the SCR-type on a dimmer per lamp basis. Each dimmer and its associated series-connected lamp is directly connected to a respective power outlet, and a preselected group of the dimmers is controlled in unison by a common time-variable pulse generator for firing the SCRs. The common pulse generator is mounted in a lighting control console, and pulse signals for controlling the dimmers are coupled by miniature coaxial signal cables to the dimmers of the preselected group. The system eliminates the power patch panels and dimmer room required in current studio lighting systems and achieves a simplification in grid outlet wiring, resulting in a significant reduction in size and cost as compared to available studio lighting systems.

Abstract: A mercury vapor electric discharge lamp is supplied with AC electric power, which is variable over a wide range, to control the lamp output power in the form of the intensity of the electromagnetic radiation emitted over a correspondingly wide range of from approximately 5% to 100% or better of rated output power without lamp extinction. An AC phase modulation control circuit controls the AC electric power supplied to the lamp such that applied voltage remains relatively constant while the current is controllably varied determined by the phase angle of conduction in the control circuit. Control of the AC phase modulation control circuit is effected in response to the actual output power of the electromagnetic radiation emitted by the lamp, the speed of a printing press or conveyor line with which the lamp may be used to cure ultraviolet sensitive inks, paints, plastics and the like on some form of substrate.

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: The low-cost lighting control apparatus for high-pressure discharge lamps utilizing an ON-OFF photocoupler to provide isolation between the relatively high voltage AC supplied to the lamp load and the relatively low voltage DC control circuitry. Preferably, the apparatus is current-feedback stabilized utilizing a feedback resistor.

Abstract: The specification discloses a circuit which produces a gradual increase or decrease in the alternating current power applied to a series connected load. Double time constant gating circuitry and capacitor integration may be utilized in combination with self-heated thermistors to effect a gradual change in the conduction duration of a series connected control element.

Abstract: A light dimmer product is provided having simpler construction and simpler assembly than prior art dimmers. Simplicity of construction is achieved by providing a printed circuit board and mounting all electrical leads from components to the board to permit a single soldering operation to solder all leads simultaneously. Simplicity of assembly is achieved by mounting portions other than current carrying portions to the mounting bracket of the dimmer product as a sub-assembly to be assembled to the housing. When assembled, the bracket support components by portions other than current carrying portions and the current carrying portions of these same components support the printed circuit board. The printed circuit board supports other components by their current carrying portions.

Abstract: A lighting control apparatus to provide variable intensity light from high pressure discharge lamps using two high pressure discharge lamp loads connected in series to provide more widely variable intensity of light. The outputs of two ballasts may be connected in series to feed the series connected discharge lamp load. Preferably a feedback signal proportional to load current is used to stabilize operation. In addition, circuitry is preferably provided to maintain a predetermined minimum current to prevent extinguishing of the lamps from low current and "hot restrike" circuitry is provided to limit the maximum load voltage when the lamps are extinguished.

Abstract: Lighting control apparatus for controlling the light intensity of high-intensity-discharge (HID) lamps operated from an AC source while eliminating the tendency for such lamps to extinguish during the dimming thereof. The apparatus comprises a variable reactive ballast controlled with respect to its reactance by a solid-state switching device which is responsive to a timed control signal provided by a signal generating device operating from the same AC source. A lamp voltage sensing device develops a feedback signal which varies in accordance with the voltage drop across the lamps being ballasted. A signal sensing and overriding device combines the feedback signal and the timed controlled signal and causes the feedback signal to override the timed control signal before the lamp voltage reaches such value as might cause the lamp to extinguish.

Abstract: An illuminating device for a microscope provided with a lighting control circuit controlled by changing the firing angle for which an impedance means is inserted between the output side of said lighting control circuit and primary side of the transformer in order to obtain a gentle rising curve for the current at the time of firing, thus to reduce the noise.

Abstract: This invention relates to circuitry for the connection of a load to and disconnection of a load from an AC power source. The circuitry is specifically useful in the on/off control of such as incandescent lamps, but not exclusively so, and provides for the timed disconnection of a load when the load is connected in series with the circuitry and AC power source, or alternately provides for the timed reduction of power delivered to the load.

Abstract: A fluorescent lamp is operated by a-c pulses having a pulse length sufficiently short that the lamp acts like slightly positive impedances. A pulse modulator which produces the pulses has a power transistor biased to saturation. However, varying the base drive of the saturated transistor causes a generally linear change in tube current to permit tube dimming and control. A servo circuit provides feedback control of the base drive to automatically compensate for variable effects to maintain constant tube lighting. Tube dimming is obtained by adjusting the feedback circuits of the servo.

Abstract: A solid state dimmer for fluorescent lights with standard (non-dimming) ballasts. Dimming is adjusted by changing the resistance in a capacitor charging circuit. Features include a trimming adjustment for eliminating flicker, a voltage regulator compensating for line voltage change, a sequential switch which allows the lamp to heat up before being dimmed, and a diode varistor, zener thyrector or the like in the charging circuit which supply additional charging current as the dimming is increased. The dimmer mounts in the same outlet box as a conventional toggle switch and can be substituted for the switch in an existing installation without changing the ballast. The dimmer is also useful for other loads requiring a variable voltage.

Abstract: Disclosed is a lamp-dimmer which employs a novel circuit to provide a digitally selected and phase-shifted trigger-impulse for firing a triac.