Abstract: A duty cycle power control circuit for a magnetron including a power transformer having a primary winding, a secondary anode winding for supplying anode voltage to the magnetron and a secondary filament winding for energizing the filament of the magnetron. In the illustrative embodiment the power transformer primary winding comprises a main winding and a serially connected standby winding. Duty cycle controlled switching devices are effective in a standby state to connect the main winding in series with the standby winding across an external power supply and are effective in the power on state to disconnect the standby winding and connect the main winding directly across the external power supply.

Abstract: A rapid-start fluorescent lamp includes a circuit breaker having a pair of electrical conductors sealed into a bulb and connecting a lamp lead to the electrode of the lamp. The circuit breaker includes first and second electrical conductors and a bi-metal strip having a first end portion connected to a first conductor and a second end portion connected to a second conductor at ambient bulb temperature, disconnected therefrom at a higher given range of temperatures, and the portion of the bi-metal strip intermediate the end portions connected to the second electrical conductor at temperatures higher than the given range of temperature.

Abstract: A Varistor (which is a non-linear impedance means) is connected in series with the primary winding of a current-transformer; and this series-combination is connected across the fluorescent lamp to be started. Before the lamp starts, the voltage across it is limited in magnitude by the voltage-clamping effect of the Varistor; and the current then flowing through the Varistor is transformed by the current-transformer and applied by way of separate secondary windings to each of the lamp's cathodes for heating thereof. A special high-voltage tertiary winding on the current-transformer provides for lamp starting aid voltage.Thus, the lamp may be gently and rapidly started in the Rapid-Start mode.However, as soon as the lamp starts, the voltage across the lamp diminishes to a magnitude lower than that required for current to flow through the Varistor.

Abstract: A rapid-start fluorescent lamp has a thermally-sensitive circuit breaker disposed thereon for disconnecting the electrodes of the lamp from an energizing source at a given range of bulb temperatures and for connecting the electrode to the energizing source at bulb temperatures above and below the given range of bulb temperatures whereby the electrodes are energized during lamp manufacture and until conductivity of the lamp is established.

Abstract: A rapid-start fluorescent lamp includes a pair of spaced electrodes within an envelope with one electrical lead connected to an electrode and the other lead coupled to the electrode by a thermally-sensitive bi-metal strip whereby one end of the bi-metal and one end of a conductor are formed to provide a straight member within a U-shaped member such that the straight U-shaped members are in electrical contact at temperatures above and below a given range of temperatures and electrically disconnected at the given range of temperatures.

Abstract: An energization arrangement for a discharge lamp includes a DC/AC converter to which a discharge lamp (81) is connected. The lamp is shunted by a relay contact (90) to obtain an electric circuit through which two electrodes (83, 84) of the lamp can be preheated. It is advantageous to insure that the relay contact is closed before a voltage occurs between the electrodes of the lamp. This prevents the lamp from exhibiting a transient flash at too cold electrodes. A timing circuit (40-47) ensures that the relay contact remains closed for about 1 second, after which the lamp ignites with warm electrodes. No electrical losses occur in the relay winding (30) during operation of the lamp.

Abstract: A rapid-start fluorescent lamp includes a pair of spaced electrodes within an envelope having a fill gas and a phosphor-covered inner wall surface with a circuit breaker having a glass bulb with a wall thickness in the range of about 0.016 to 0.018 inch positioned within the fluorescent lamp.

Abstract: A d.c.-a.c. inverter circuit allows a standard type fluorescent lamp to be operated from a low-voltage source of d.c. power with a high degree of efficiency attributable in part to use of lamp current as base drive current for a power transistor controlling the energization of a transformer primary winding having two mutually connected secondary windings which apply voltages across the lamp through the power transistor. Additional efficiency is achieved by use of a second transistor under time delay control for supplying preheat current to the lamp and turn-on current to the power transistor only during the starting phase of lamp operation.

Abstract: A circuit breaker for a rapid-start fluorescent lamp includes a pair of electrical conductors sealed into a glass bottle, a bimetal switch within the bottle having one end affixed and the other end contacting the pair of electrical conductors and a meltable by-pass element shunting the pair of electrical conductors and formed of a material having a relatively high cold resistivity and a low temperature coefficient of resistance.

Abstract: In an auxiliary-voltage DC source for supplying an electric circuit and, more particularly, one at a high potential in an electron gun without an isolation transformer, the primary winding of a current transformer is located in an alternating-current section of the electric circuit. The current transformer has at least one secondary winding which is connected through a rectifier to a parallel regulator for providing the auxiliary-voltage.

Abstract: A rapid start fluorescent lamp having a glass envelope with a phosphor coated inner surface, a low pressure gas fill and an electrode at each end includes at least one electrode disconnected switch having a bimetal switch normally closed at room temperature and open at a predetermined temperature higher than room temperature with the bimetal switch connected to the electrode and to an electrical lead extending from the lamp to an energization source.

Abstract: An energy-saving instant-start series-sequence fluorescent lamp system includes power-reducing capacitor means connected in series circuit arrangement with one or both lamps in a two-lamp system. A protective device is connected in circuit with a first lamp of the system so that in the event the second lamp fails to operate and causes a high current to flow through the first lamp, the protective device reacts to prevent the system from being damaged. A lamp incorporating the power-reducing capacitor and protective device is also disclosed.

Abstract: A plurality of heater elements are heated using a DC voltage to render the display brightness of a fluorescent indicator tube uniform. A circuit comprises a first circuit for intermittently applying a heater current to the indicator tube at a predetermined interval, and a second circuit for preventing the indicator tube from developing a display during heating the heater elements.

Abstract: A picture display device including a picture display tube and a circuit for supplying the heater thereof with an increased heater voltage during a predetermined warming up period. The heater is connected to the secondary winding of an (auto) transformer, the primary winding of which is connected to a terminal of an a.c. voltage source, for example a winding provided on a line output transformer, the other ends of the primary and the secondary windings being interconnected and connected to a positive temperature coefficient thermistor and the other ends of the heater and the thermistor being connected to the other terminal of the source. The secondary winding has more turns than the primary winding.

Abstract: The invention provides a power source device for an ion source, including first to third power source units coupled to the anode, the cathode and the beam extraction electrode of the ion source. The second power source unit applies an alternating voltage across the cathode. An alternating heating current then flows through the cathode. Each cycle of the alternating voltage from the second power source unit has positive and negative components with preset levels which are generated with a predetermined time interval between them. The power source device further includes a control circuit for interrupting the operation of the first and third power source units during the predetermined time interval.

Abstract: A magnetic transformer switch which switches its primary flux path upon conduction in its secondary and the combination thereof with a fluorescent lamp in which the heater current is reduced upon lamp ignition by reason of the current in the heater winding in the secondary being reduced upon the primary flux path being switched. A unique construction minimizes both electromagnetic interference and induction losses.

Abstract: A ballast circuit for a fluorescent lamp including a gaseous discharge light bulb which for a given input power produces a decreasing amount of light as the bulb temperature decreases below a designed operating temperature at which the amount of light produced is a maximum, the ballast circuit being adapted to be connected in series with the bulb and having a first impedance at the designed operating temperature.

Abstract: The invention relates to starting and supplying a low-pressure discharge lamp which comprises two electrodes between which a main discharge path is formed, a shunt path being electrically in parallel with at least a portion of said main discharge path.In accordance with the invention the lamp is started by means of a glow-discharge starter which is shunted by a VDR the threshold voltage of which is lower than a value determined by the geometry of the shunt path, and is higher than the minimum voltage for starting a discharge in the main discharge path. The discharge then only starts in the main discharge path.

Abstract: The present invention relates to a medical X-ray radiation power supply apparatus wherein a DC-operated switching circuit is connected at the primary side of a high voltage transformer, and a comparator circuit compares the voltage predetermined by a tube voltage setting circuit with an actual tube voltage detected by a tube voltage detector circuit, then the gain of a comparison voltage is raised so that the actual tube voltage can quickly reach the predetermined tube voltage value, thereby tube voltage errors, which are caused by short photographing time in a medical or breast X-ray photographing apparatus, are eliminated.

Abstract: To prolong the life of a deuterium gas discharge lamp and reduce photometric noise, a DC potential is applied between the cathode and the anode of the lamp to support the arc current through the tube and a separate AC potential is connected across the cathode through an AC amplitude control circuit that controls the amplitude of the AC current. While the cathode is at room temperature, a potential proportional to the AC current through the cathode is balanced against a potential proportional to the AC potential drop across the cathode in an operational amplifier circuit and the output used to operate an indicating device. During operation of the lamp, the output of the operational amplifier circuit is used to control power applied to the cathode through the AC amplitude control circuit.

Abstract: A zero-crossing signal is generated in response to the zero-crossing of the current of an AC power source of a magnetron oscillator, and in response to the zero-crossing signal a triac connected between the magnetron oscillator and the AC power source is turned on to generate a microwave. The triac is turned off when the voltage of the AC power source becomes lower than a holding voltage of the triac.

Abstract: A circuit for starting and operating fluorescent lamps from an a-c power source, comprising reactive ballast means connected to ballast the lamps and having a non-linear characteristic for producing harmonics of the power source frequency, and a capacitor and a cathode heating transformer connected in series and connected to receive power from said ballast means and resonant in a frequency range including two or more of said harmonics. A switch may be connected in series with the capacitor and cathode heating transformer for opening the cathode heating circuit when the lamps are operating, to conserve electrical energy.

Abstract: Disclosed is an electron beam current stabilizing device comprising a sensing element (12) responsive to the beam current deviation from the predetermined value, a saw-tooth voltage shaper (14) connected to a high-voltage transformer (2) of an acceleration voltage source and providing periodic saw-tooth voltage, smoothly sloping portions thereof being shaped starting from the moment when the voltage at the high-voltage transformer (2) crosses zero, an adder (13) whose one input is connected to the output of the sensing element (12), and the other input, to the output of the shaper (14), a threshold element (15) connected to the output of the adder (13), a differentiator (16) connected to the output of the threshold element (15) to shape the electric driving pulses when the smoothly sloping portions of the saw-tooth voltage cross at the output of the adder (13) the threshold level of the threshold element (15), a light source connected to the output of the differentiator (16) to convert the electric driving pu

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 low cost high frequency electronic dimming ballast for gas discharge lamps is disclosed which eliminates the need for external primary inductance or choke coils by employing leakage inductance of the transformer. The system is usable with either fluorescent or high intensity discharge lamps and alternate embodiments employ the push-pull or half-bridge inverters. Necessary leakage inductance and tuning capacitance are both located on the secondary of the transformer. Special auxiliary windings or capacitors are used to maintain necessary filament heating voltage during dimming of fluorescent lamps. A clamping circuit or auxiliary tuned circuit may be provided to prevent component damage due to over-voltage and over-current if a lamp is removed during operation of the system.

Abstract: An improved output configuration for a multiple-lamp electronic ballast system. The output includes a differential transformer having a primary adapted to be coupled in a first loop including a first filament filament drive winding and feedback winding and a secondary adapted to be coupled in a second loop that includes a second filament, filament drive winding and feedback winding.The improvement allows the entire ballast to be shut down when a lamp has been removed thereby avoiding aberrant oscillator operation under abnormal, yet predictable, lamp load conditions.

Abstract: A low cost, high frequency, solid-state dimmable fluorescent ballast is disclosed which utilizes a resonant bridge inverter to provide high frequency sinusoidal power to the lamps. One embodiment of the invention includes auxiliary windings connected to the filaments of the lamps to be powered which utilize the inductance of the resonant bridge inductor coil to maintain the voltage across the filaments during dimming. A clamping circuit or auxiliary tuned circuit may be provided to prevent damage due to an over-voltage and over-current condition upon removal of a lamp during operation of the system. In an alternative embodiment, the auxiliary windings, are replaced by capacitors across each of the lamps to be powered. This also eliminates the need for the clamping circuit. If desired, a current splitting capacitance system may be used. Pulse width modulation of the inverter drive or variable AC or DC power supply input may be used to accomplish dimming.

Abstract: A parallel circuit of a capacitor and a switching element is connected to a hot cathode discharge lamp lighting device using a high frequency and high voltage generating means for permitting the flow of current into the filaments of the hot cathode type discharge lamp only at the lamp starting time. The switching element of the parallel circuit is a current controlled resistance element, such as a switching semiconductor, having a break-over voltage V.sub.BO lower than the capacitor terminal voltage during the initial ignition period and higher than the capacitor terminal voltage during the reignition or operation period, whereby the filament current to the discharge lamp may be used for preheating of the filament in the initial ignition period. The filament current may be stopped or reduced by turning off of the switching element by raising the terminal voltage of the capacitor in the reignition period during normal operation.

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: Energy-saving circuitry for a rapid-start fluorescent lighting system includes a reactance-modifying capacitor coupled in series with first and second fluorescent lamps and includes a filament switch which is operative to conduct filament heating current during starting of the first lamp. The filament switch is coupled between filaments at opposite ends of the first fluorescent lamp and triggers to a low impedance state in response to the lamp starting voltage. A capacitor bypass switch can be coupled in parallel with the reactance-modifying capacitor to reduce the impedance of the series circuit during lamp starting.

Abstract: A glow bottle starter having three lead-in wires and containing two bimetals connected together at one end and a rigid tungsten rod. The bimetals make normally closed contact with the tungsten rod in the quiescent state of the starter, and upon electrical current flow through one or both of the bimetals to cause elevation to a predetermined temperature, the bimetals are operative to separate from the tungsten rod. In a circuit including the glow-bottle starter for starting a discharge lamp, one of the bimetals and the rigid tungsten rod are connected across the output of a ballast circuit, and the tungsten rod and other bimetal are connected across the lamp.

Abstract: A high pressure sodium lamp, which includes a discharge tube enclosing xenon at pressures in excess of 300 torr, is reliably started by the combination of an igniter, a conductor wrapped around the discharge tube, and a switching circuit. The igniter provides periodic pulses of 2500 to 4000 volts with a duration of at least one microsecond. The switching circuit provides a high voltage pulse having an amplitude about equal to the amplitude of the periodic pulses and a duration much greater than the duration of the periodic pulses. The conductor intensifies the electric field within the discharge tube. A conventional lamp ballast provides ac power during starting and normal operation.

Abstract: In an electron beam machine for e.g. beam welding, the beam current I.sub.em is stabilized by negative feedback applied to the grid of the electron gun. The optimum cathode heating current is ascertained by causing the cathode heating current I.sub.H to decrease steadily from a maximum value. The beam current is kept constant by the feedback, which adjusts the grid voltage U.sub.W to offset the decrease in cathode temperature caused by the decreasing heating current; the rate of change of the grid voltage U.sub.W is monitored, and when this rate of change exceeds a threshold, the decrease in heating current is arrested, and the heating current is maintained at the thus established optimal value or preferably set at a slightly higher value, which secures an extended length of life of the cathode. This setting of the cathode heating current is repeated after a predetermined interval of time to establish a new value in response to a change of the condition of the cathode.

Abstract: A system for the control of power of a high-voltage electron beam generator having a cathode and a control electrode for the cathode, has a controller at ground potential, a pulse generator for the production of square-wave voltage pulses symmetrical with ground potential, a transformer for transferring high-voltage potential to the beam generator including a primary winding substantially at ground potential and a secondary winding at high-voltage potential, a full-wave rectifier connected to the secondary winding and a filter connecting the rectifier to the cathode and to the control electrode. The filter comprises an LC combination of at least two LC members connected in series, in conjunction with at least two capacitors, one parallel to the cathode-control electrode and the other parallel to the full-wave rectifier, the resonance frequencies of the LC members being in a ratio of approximately 2:1.

Abstract: A high frequency and high voltage generating circuit for a discharge lamp lighting device controls its initial output at the starting time of a discharge lamp to prevent applying a high voltage to the discharge lamp in the "cold cathode" state. The circuit comprises in combination an oscillation circuit having an oscillation capacitor, a non-linear inductor and a thyristor, and an initial output limiter for delaying the output supply until the lamp filament is sufficiently preheated for preventing sputtering and for extending the operational life of the discharge lamp. The output control is formed as a bias circuit for the nonlinear inductor and includes a thermistor with a negative or a positive temperature coefficient.

Abstract: A high-intensity discharge lamp which has a lamp current-interrupting device in series circuit with the arc tube which is sensitive to any breach occurring in the protective outer envelope. The current-interrupting constituent of the device initially incorporated into the lamp comprises vanadium sesquioxide. The device has predetermined dimensions and an initial predetermined operating resistance. During normal operation of the lamp the device operates at a predetermined temperature sufficiently low so that said device is stable in the presence of the non-reactive atmosphere enclosed by the outer envelope. The predetermined temperature also being sufficiently high so that upon a breach occurring in the outer envelope permitting oxygen to enter, the vanadium sesquioxide rapidly converts to vanadium pentoxide to interrupt the continuity of the power circuit to the arc tube and prevent the operation of the lamp.

Abstract: Add-on device for connection in series with one lamp of a two-lamp rapid-start fluorescent light system to reduce by a predetermined amount the nominal power consumption and light output of the system. The device has normally closed relay contacts which are in circuit with one of the electrodes of one of the lamps and a power-reducing capacitor is in shunt with one of the relay contacts. Upon turning on the system, a solid-state time-delay and relay-coil-energizing circuit is actuated which opens the relay contacts only after the lamps have been started and are operating with nominal power consumption. This places the shunt capacitor in series with the operating lamps and reduces the nominal power consumption by a predetermined amount.

Abstract: An arrangement for starting and operating a low-pressure mercury vapor discharge lamp provided with preheatable electrodes. The lamp is supplied from a battery via two direct-to-alternating current converters connected between the battery and the lamp. One converter is a voltage-controlled converter which exclusively effects the preheating of the electrodes, whereas the other converter supplies the lamp current only. This arrangement provides reliable ignition and operation of the lamp even in the case of a large variation in the battery voltage.

Abstract: An apparatus for heating the cathode of an electronic power tube, having a supply for delivering a heating current to the cathode, an interrupter circuit for periodically interrupting the flow of heating current to the cathode, and controls for controlling the duration of these periodic interruptions and for regulating the net amount of heating current. To achieve this, the controls include a voltage control that varies in such a way so as to bring the heating current from a value of O to Io (where Io is the correct heating current at which the tube will be in a pre-heated condition) during a first, predetermined time period, and then from a current Io to a current Im (where Im is the optimum value for the heating current when the tube is normally operating), during a second predetermined time period.

Abstract: A filament heating apparatus for an X-ray tube having an isolation transformer through which a control signal is digitally transmitted regulates the filament current to be constantly stable. The control signal is comprised of one of a reference signal based upon the characteristics of the X-ray tube and a component of the filament current.

Abstract: An ignition trigger circuit for luminous and fluorescent discharge tubes, especially for cold electrode tubes. The ignition pulses are generated by placing across the gas discharge tube a relay-activated switch. The relay windings are connected in series with a rectifying diode and a capacitor across the A.C. power source. When a charging current flows into the capacitor, the relay windings are actuated at each A.C. cycle. By suitable choice of the electrical dimensions, the charging phase of the capacitor may be extended over several A.C. cycles, thereby causing repeated actuations of the relay and closures of the switch. Once the charging current falls below the holding current of the relay, the short-circuiting switch stays open permanently. A discharge resistor is provided to return the circuit to its initial state after being removed from the A.C. current source.

Abstract: A indicator device with vacuum fluorescence elements controlled or triggered by a driving circuit, the heaters of the elements lying in a heating circuit. The heating circuit contains a switch which is controlled or triggered by a clock generator and the clock pulse frequency and the pulse duty factor of the control signal pulses are selected such that the effective value of the pulsed heating current is equal or approximately equal to the dc heating current in accordance with the elements.

Abstract: An electric discharge lamp circuit arrangement wherein rapid starting of the lamp is obtained by charging a ballast impedance capacitance via a unidirectional current conducting path in a sense such as to breakdown a voltage breakdown device in the control electrode lead of a controllable switching device connected with the lamp to provide a current path between the supply terminals comprising, in series, the capacitance, heating means for the lamp main electrodes and the switching device. On breakdown, the switching device temporarily conducts to complete the series path and cause a pulse of current to flow through the heating means, whereafter the capacitor recharges and a further current pulse is produced. The unidirectional current path may extend through the breakdown device or by-pass the breakdown device via a rectifier.

Abstract: An inductive stabilization ballast for a low-pressure mercury vapor discharge lamp having preheatable electrodes. The ballast includes a protective device which comprises a positive temperature coefficient resistor. The inductive portion of the ballast and the PTC resistor are disposed in the ballast so as to be insulated relative to one another, both electrically and thermally. The PTC resistor is connected in series with a glow starter in the preheating circuit of the lamp electrodes. Thus, the electric current in the case of a non-starting lamp is kept at a harmless low level and, in the case of a normally operating lamp the PTC resistor does not disturb the lamp operation.

Abstract: An HID lamp utilizes a thin, fragile, strip-like conductor member affixed to and carried on a portion of the inner surface of the lamp protective envelope. Upon breakage of the protective envelope, the fragile conductor will break and interrupt the electrical continuity of the lamp's electrical circuit, thereby rendering the lamp inoperative.

Abstract: The invention relates to a starter for igniting a low-pressure sodium lamp. The starter is provided with an oscillator circuit consisting of an electric coil, a first capacitor and a controlled semiconductor switching element.In accordance with the invention the starter also comprises a parallel circuit of a resistor having a positive temperature coefficient and a second capacitor, this parallel circuit and the oscillator circuit being in series. This series circuit is connected between two electrodes of the lamp. In the case where a defective lamp must be replaced by a new lamp--the supply voltage being switched on--in spite of the hot state of the resistor with positive temperature coefficient a plurality of starting pulses will nevertheless be passed through the second capacitor to the new lamp whereafter this lamp can ignite.

Abstract: A control device for controlling the emission current of an x-ray tube comprising a control circuit which receives a digital reference value signal and an amplifier whose gain is controlled by a portion of said digital reference value signal so as to provide a comparatively high accuracy for the emission current adjustment with a minimum number of binary positions.

Abstract: An electrical circuit for operating an electrical discharge lamp has a pair of terminals for connection to a supply of voltage of substantially sinusoidal waveform, a second pair of terminals for connection with a discharge lamp, a ballast impedance connected between one of the first pair of terminals and one of the second pair of terminals, a starting device for aiding initiation of discharge in the lamp and means for disabling the starting device when a discharge has been initiated in the lamp. The means for disabling the starting device operates in response to a change in the voltage waveform across the second pair of terminals from substantially sinusoidal to substantially square.

Abstract: There is provided in combination with a rapid-start series-sequence type ballast for two low-pressure mercury discharge lamps, apparatus for reducing the power consumption of both lamps. The apparatus utilizes switch means in conjunction with a capacitor to limit the current supply to the lamps after the lamps are energized. The switch means has two members in series circuit arrangement with one of the electrodes of one of the lamps. Each member is connected on opposite sides of the electrode. The capacitor is connected in parallel circuit arrangement with one of the members. Initially upon energization the switch means has a low impedance state to permit current flow and then switches to a high impedance state. The switch means permits preheating of the electrode and thereafter upon response to current flow switches and causes the lamp current to pass through the capacitor and thereby decrease by a predetermined amount the current through the normally operating lamps.

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.