FR2472902A1 - ARC LAMP LIGHTING DEVICE WITH HIGH AND LOW FLASHING LEVELS - Google Patents

Abstract

HIGH AND LOW ILLUMINATION LEVEL DEVICE, EXCITED BY A CLASSIC SOURCE OF ALTERNATIVE CURRENT. IT INCLUDES A RECTIFIER BRIDGE 15, A FIRST FILTERING CAPACITOR 16, A MAIN ARC LAMP 11, A RESISTANT FILAMENT 12, A TRANSFORMER 28, A FIRST DIODE 23, A MONOSTABLE SEMICONDUCTOR SWITCH INCLUDING A FIRST TRANSISTOR 27, A DEVICE RECTIFIER 45 AND A MEDIUM 46, 49, FOR KEEPING THE SEMI-CONDUCTIVE SWITCH IN THE NON-CONDUCTIVE STATE WHEN THE ADJUSTMENT IS AT LOW LEVEL. APPLICATION TO GENERAL LIGHTING.

Description

1 247'2902

  The present invention relates to a lighting device

  at low levels of illumination, excited by a

  this classic AC power and in which the main

  pale light source is an arc lamp supplemented by a filament auxiliary lamp providing illumination during the ignition-of the arc lamp and during use at low

level of illumination.

  The present invention relates to a lighting device

  ge in which the main light source is a high-pressure discharge lamp whose efficiency can reach

  up to six times that of an incandescent lamp. Lamps

  High pressure metal vapor pumps have been used for some time in high power installations. Recently, it has been developed as disclosed in United States Patent No. 4,161,672, lamps

  smaller, low-power, metal halide

  with efficiencies similar to those of larger lamps. We can substitute such lamps

  to the incandescent lamp with better energy efficiency

tick.

  The power supply of the lighting device de-

  written here is provided by a high-frequency power supply

  quence in which a ferrite transformer controlled for

  out of saturation operation, a switch to

  tor and a trigger oscillator are the components

basic.

  The settings of the high and low levels of the dis-

  Positive lighting by inserting one or two resistors in series with the arc lamp. The present invention relates to an alternative to the light dimming problem in which the low level of illumination is provided by a

  incandescent element and the high level by the arc lamp.

  It is obviously desirable that the lighting device be usable in a conventional socket as well as in

a three-way socket.

  The objectives of the invention are achieved in a device

  lighting fixture with three terminals for the separate connection

  lective to AC power and incorporating a redesigned bridge

  equipped with a pair of AC input terminals and a pair

  of DC output terminals with a first capacitor of

  connected to the DC output terminals.

  The lighting device further comprises a main arc lamp connected in a series circuit between a node and the common output terminal of the bridge or earth, and a resistive filament connected in a series circuit between the

  positive output terminal of the bridge and the node. With the

  low level, the filament provides illumination of

  low intensity. With the high level setting, the

  provides auxiliary lighting during main lamp ignition and ballast action for the lamp

with bow.

  The lighting device also includes a transfor-

  an electric generator having a primary winding connected in a series circuit between the positive output terminal of the bridge and the node and anode of the lamp; a first diode

  connected in the series circuit between the first node and the

  a lamp node with a polarity ensuring the conduction of the current of the main lamp through the filament and in parallel with the second winding to straighten the transformed potentials; a semiconductor switch

  monostable, normally non-conductive, connected in a circuit

  baked series between the knot and the earth, the function-

  intermittently of the switch producing pulsed current through the filament for auxiliary lighting, a

  alternating potential in the primary winding, and a

  alternating current transformed in the secondary winding, rectified by the first diode and applied to the anode of the

  main lamp for ignition; a device to

  such as a thyristor or a transistor or diode, connecting the node to the third terminal of the illumination device with a polarity allowing the conduction of a half-period through the rectifier bridge and the filament for illumination at incandescent when the setting is on

  low level, and means for holding the semiconductor switch

  conductors in the state of non conduction on the setting

low level.

  In a recommended form, there is provided a trigger oscillator responsive to the electrical state of the main lamp to cause intermittent operation of the switch for lighting the lamp; it comprises a second transistor in an oscillating configuration, a resistance voltage divider connected in series between the node and the earth, and a detector resistor of the current in the lamp, connected between the cathode of the lamp and the ground. The base of the second transistor is connected to a lower tap of the voltage divider for the detection of the

  voltage at the terminals of the arc lamp, and the transmitter of the

  transistor is connected to the sensor resistor of the capacitor

in the arc lamp.

  If the rectifying device is a diode, the rectifying means

  controlled keeping the semiconductor switch in the nonconductive state, when the setting is on the level

  low illumination, consists in maintaining the oscillator

  clutch in the state of non-oscillation. These measures

  includes several diodes and resistors and a second conden-

  sateur. The cathode of a second diode is connected to the third

  the second terminal of the luminaire and its anode is

  linked to the positive terminal of a second capacitor whose

  negative terminal is grounded. The cathode of a third

  the second diode is connected to the anode of the second diode and its

  anode is connected to an upper terminal of the voltage divider

  if we. These components prevent the oscillator from

  operate while the setting is on the low level.

  A second resistance connected between the first

  first node and the second capacitor to charge it to a reverse bias value of the second diode and

  decoupling the second capacitor from the voltage divider

  as the setting is on the high level of illumination.

  This allows an immediate response to the transients of the

  during normal operation of the lamp, not re-

delayed by the second capacitor.

  A third resistance is planned, in parallel with

  the second capacitor, chosen to maintain a polari-

  reverse convection on the third diode in normal operation.

  harm and reduce excessive tension on the second

  when the setting is on the high level.

  Between the DC output terminals is a pair of diodes r. elies ensérie with their point of inter-

  connected to the third terminal of the lighting device

  ge. This provides protection against sector transients when only the first and third terminals of the

  lighting device are connected to the AC source, and also

  if overcurrent protection on ignition

  when the lighting device is put into operation initially

  LEMENT. The lighting device described so far can be mounted on a three-way socket, the first terminal to the pellet on the socket and the third to the annular contact of the socket. Thus connected, the lighting device can

  successively occupy the settings at low, high and low-

calves of illumination.

  If the rectifier device is a thyristor, the recommended means for maintaining the semiconductor switch in the non-conductive state while the setting is on -low level of illumination, operates by preventing the establishment

  at the terminals of the filter capacitor, a sufficient voltage

  to turn on the trigger oscillator.

  By thus using a thyristor, the lighting device can successively occupy the settings at low, high and high.

levels of illumination.

  The remainder of the description refers to the figures

  1, an illustration of an original lighting device with low and high adjustment of the level of illumination,

  suitable for connection to a standard lamp socket

  Three-way or three-way and using as a light source an arc lamp on the high level setting and a filament incandescent light source on the low level setting; Fig. 2A, a circuit diagram of the lighting device with built-in low-profile power supply,

  and whose connections are provided for a three-socket

  channels; Fig. 2B, a table of switch and lamp states when the original lighting device is used on a three-way socket and has a sequence of low, high and low light levels, FIG. 3, a ferrite transformer which is an essential element of the power supply; Fig. 4A, an electrical diagram of another possible embodiment of the invention; and 4B, a table of the states of the switch and the

  lamp corresponding to the diagram of Figure 4A.

  Referring now to Figure 1, we can see

  the representation of an original lighting device intended

  to operate on a low frequency AC voltage source

  this (50-60 Hz) classic. This device is composed of a mountain

  lamp-lighting unit and a power supply unit that provides electrical power to the lamp assembly. The

  device has two levels of illumination: high and low,

  selected by a three-way switch in the socket of

  the lamp. The lamp assembly comprises a green envelope

  re 9 containing a high efficiency arc lamp 11 and a resistant filament 12 providing both ballast and light production functions. The power supply unit comprises a rigid housing 10 fixed to the glass envelope and a "three-way" screw base 14. The base 14 is a conventional "three-way" base, normally used with three-level lamps illumination. The base has three connection points comprising a screw-in portion 6, an annular contact 7 and a d-chip. The base ensures both the electrical connection and the mechanical fixing of the

  lighting device in a lamp socket "three-

tracks "classic.

  The power supply provides excitation of the filament and the arc lamp. With the high level setting, the

  power supply produces the excitation required by the lamp.

  main factor in the conditions of ignition and

  and provides immunity from certain transi-

  sector. Similarly, with the high level setting, the power supply provides the energy needed for

  production of additional light by the filament

  but only as long as it is necessary

  ignition. When the setting is low, the power supply provides the light producing energy by the filament, continuously, and does not provide power

to the main arc lamp.

  Filament and arc lamps are individually

  at low and high illuminance levels, respectively

  except during high level lighting, where both lamps contribute to lighting. The low level of illumination is provided by the filament light source and the high level of illumination by the arc lamp. In the low level setting, the arc lamp is off and the lighting is provided by the single filament. With level adjustment

  high, the luminaire can be put into operation,

  light, or put off keeping the same production

  immediate light only with an incandescent element. Pen

  the time required for the arc lamp to reach its

  maximum brightness after a cold start, or the periods

  lengths required for hot ignition,

  additional incandescence rage is provided by the source

luminous filament.

  The arrangement of the elements in the lamp assembly is well illustrated in FIG. 1. The arc lamp 11 and the 60-watt filament 12 are both installed in one and the same glass bulb 9. The elements 11 and 12 are supported by conductors sealed in the base of the lamp assembly. The gas filling the bulb 9 is an inert gas suitable for a conventional incandescent lamp. The arc lamp 11 is shown with its positive electrode or node down (near the cap) and its negative electrode or cathode up (away from the cap). The two electrodes are, in turn, sealed at the ends of a small

  of quartz whose circumference is cylindrical except in a small central zone

  of larger section, less than 12.7 mm in diameter

  be. The interior of the arc lamp, which is not particularly illustrated, has a spherical central chamber or

  elliptical filled with an ionizable mixture: argon, gas of

  ionizable lumen, mercury that vaporizes when it is hot, and a vaporizable metal salt such as sodium iodide or scandium. During operation, an arc is formed

  between the electrodes and produces a light in the chamber.

  Small, low-power lamps of the type that have just been

  described are called halide or steam lamps

  metallic. A more complete description of a suitable lamp

  is given in the patent of the United States of America

No. 4.161.672 cited above.

  During normal operation in the final regime, the energy

  The light supplied to the arc lamp is in DC with a slight BF ripple (50-60 Hz). On ignition or re-ignition, the voltage supplied to the arc lamp and the filament has a high frequency AC component and arrangements are made to avoid prolonged ignition as might occur in the event of a failure.

  of the arc lamp prevents priming.

  The arc lamp has several distinct states in

  conventional use and each active state requires an ex-

  separate quote. From a practical point of view, the arc lamp has three essentially active states, called Phases I to III,

and an inactive state.

  In phase I, "priming" occurs. The duration of the priming should not exceed one or two seconds and often it is shorter. This is the time needed

  for a suitable high voltage to cause the "decomposition

  electrical supply "of the gas contained in the arc lamp in order to

  trigger a decreasing maximum voltage at its terminals.

  This last condition is also called establishment

a "glow discharge".

  Phase II - transition between the discharge and the arc -

  lasts from one tenth of a second to, possibly, two seconds, and is characterized by a higher level of ionization and a lower maximum voltage. When phase II begins, the discharge is generally unstable, oscillating between a maximum value and a minimum value, the discharge voltage decreasing continuously to a lower maximum with a minimum recurrence of around 15 volts. The average level of conduction of the gas increasing,

  the maximum voltage of the lamp decreases, the power consumes

  it increases as well as the temperature inside the lamp. When the maximum arc voltage falls to values

  about 200 to 400 volts, higher energy (generally

  2 watts to 4 watts) is necessary in the case of

metal vapor.

  Phase III begins with the establishment of the "arc" that occurs when part of the cathode has reached

  thermoelectronic emission temperatures. At the moment

  During the transition from phase II to phase III, the discharge voltage loses its unstable behavior and remains at an initial value of approximately 15 volts. During phase III,

  the lamp has a constant low-impedance and a

  current is necessary to avoid a warm-up

  excessive. At the beginning of phase III, the dissipation of the

  pe is fixed between 10 and 15 watts and a large production

of light begins.

  The warm-up period, which is the part

  phase III, normally lasts 30 to 45 seconds.

  of. During this period, the lamp reaches its maximum operating temperature and the contained gases reach their final operating pressure. The voltage across the lamp increases to a normal value of 87 volts; this is accompanied by some reduction in the conductance of the lamp. As soon as the final conditions

  the lamp absorbs the maximum power.

  male (32 watts, in general) and the light is produced with

the maximum intensity.

  The duration of the pre-priming period is variable and has a minimum value of zero under the ambient conditions

  standard and for a maximum value between 45 seconds and 4

  if an arc failure has occurred and a

  ignition is necessary. If the lamp is de-energized during normal operation, it is at an elevated temperature and a high gas pressure for a short period of time. To reboot the arc when the lamp is hot, the required potential may be an order of magnitude higher than for a cold start (eg 10 to 30 kV). The thermal time constants of the lamp are such that the time required for cooling from a

  operating state to the point where a conventional voltage

  that (1-2kV) reboots the arc can be between 45 sec-

and 4 minutes.

  Additional incandescent lighting is particularly

  important during the longer periods of

  temperature and pre-priming, but in order to ensure

  stable lighting, it is also planned during the

  shorter ones (priming and transition between discharge and arc). The suitable energy for the operation of the arc lamp and filament auxiliary lamp is

  provided by the source represented jointly with the

  blage of the lampholder in FIG. 2A.

  The lighting device whose wiring diagram is shown in Figure 2A has as main components the arc lamp 11, the filament lamp 12, a DC power supply (14, 15, 16) for rectifying the alternating current 120V - 60 Hz, and an operating network (23-52) for the transformation of electrical energy from the

  DC power supply to the forms necessary for

  lamp assembly. The socket assembly

  lamp whose wiring is illustrated in Figure 2A com-

  takes a three-way switch 13 (switching components

  18 to 22), a lamp socket 17 and appropriate means

  required for connection to a 120-volt AC supply.

  Assembly of the lampholder is conventional.

  The black driver from the AC power supply is

  to the fixed contact 18 of the three-way switch on the left

  of the movable member 20 (as shown in Figure 2A).

  The white conductor coming from the AC power supply is connected to the screw base of the socket 17 where it makes contact

  with the screw portion 6 of the base 14 of the lightning device

  rage. The fixed contact placed on the right side of the movable member is connected by a red wire in contact with the socket which presses on the annular contact 7 of the base of the luminaire. The fixed contact 21 located below the motor moving member is connected to the contact of the socket

  which comes to touch the pellet 8 of the pellet idu device d, e-

  lighting. As shown in the figure, the movable member is a generally parallelepidea

  approximately three-sided, on which

  a continuous conductor 22. In the direction of rotation, the movable member makes selective contact with the

  fixed contacts 18, 19 and 21. In accordance with the table

  2B, the switch can take successive

  four positions. In the first position the surface

  of the mobile organ, which does not establish any circuit,

  tap on the fixed contact 18 connected to the black wire of the

  CA and the lighting device is off. Assuming a rotation in the opposite direction of the needles

  clockwise to the second position (the position illus-

  tré) the movable member 22 connects the contacts 18 and 19 between them and the black conductor of the AC power supply is connected to the annular contact 7 of the base of the lighting device. In the third position, the movable member 22 connects the contacts

  18 and 21 between them and the black driver of the

  CA is connected to the pellet 8 of the pellet. In the fourth

  position, the movable member 22 connects the three final contacts

  xes together and the black driver of the AC power supply is

  connected to the annular contact 7 and the pellet 8 of the pellet.

  From the foregoing, it can be seen that the lower input terminal of the diode bridge is at all times connected to the white conductor of the AC power supply, while the upper input terminal of the diode bridge and the third input terminal of the lighting device (annular contact 7) are connected separately or together to the black conductor of the AC power supply as shown in the table of Figure 2B. The DC power supply circuit of the lighting apparatus is conventional; it comprises a bridge rectifier 15 and a filtering capacitor 16. The voltage is supplied from a 120-volt AC source, 60 Hz, by the base 14,

  at the AC input terminals of a two-wave rectifier bridge

  these 15, in positions 3 and 4 described above. The positive output terminal of the bridge becomes the positive output terminal of the DC power supply and the output terminal

  the bridge becomes the common "earth" or terminal of

  reference DC power supply. The filtering capacitor 16 is connected between the output terminals of the bridge

to reduce AC ripple

  During operation in the final mode of the arc lamp 11, with the setting on the high level of illumination,

  the output of the DC power supply is 145 volts with a

  voltage of approximately 1/2 ampere, which gives an output power of approximately 50 watts of which 32 are dissipated in the lamp. Since the setting is high, the energy required to power the lighting device during a hot re-ignition is approximately 60 watts.

  the maximum energy required during the rise in

  The temperature of the arc lamp is about 75 watts. With the

  low level settings, power is applied to the

  lament only, using bridge 15 in rectifier mode

  alternately. In this case, the dissipation in the

  The classic 60-watt rating is approximately 38 watts.

  The operating network which receives its current from the power supply

  and, in turn, feeds the lamp assembly,

  takes the components 23 to 52 connected to each other in the following manner. The filament light source 12, the diode 23, the arc lamp 11 and the current detector resistor 24 are connected in series in the order indicated between

  the positive terminal and the common terminal of the DC power supply.

  The diode 23, with a polarity facilitating the passage of the neck,

  from the DC source to the arc lamp, has its connected anode

  at the node 26 and its cathode at a terminal of the arc lamp 11.

  The arc lamp which has a necessary polarization, has its anode connected to the cathode of the diode 23 and its cathode

at a terminal of the current detection resistor 24.

  Continuing the description of the operative network,

  find a semiconductor switch, monostable, to de-

  latching, consisting of a power transistor 27, a

  elevator transformer 28 and components 29, 30.

  power sistor comprises a base, a transmitter and a col-

  reader. The step-up transformer has a iron core

  rite allowing operation at high frequency (> 20kHz),

  a primary primary winding 31, a secondary winding

  32, a primary control winding 33 and a secondary control winding 34, all associated with the core. The function of the control windings is to control the conduction of the transistor in a direction determined by the magnetic state of the ferrite core and to produce a monostable action in order to avoid the full saturation of the ferrite core.

  core. The terminal without reference point of the primary winding

  main mayor 31 is connected by the capacitor 35 to the

  positive terminal of the DC power supply and the terminal of this

  bearing marked by a point is connected to the node 26. The

  terminal without a reference point of the primary secondary winding

  cipal of the transformer 28 is connected to the node 26 and the terminal of this winding marked by a point is coupled

  by the capacitor 36 to the anode of the arc lamp 11. The

  power transistor is connected to the untagged terminal of the primary control winding 33. The marked terminal of this winding 33 is connected to the cathode of the

  arc lamp 11. The base of the power transistor is

  connected to the cathode of a loopback diode 29 whose anode is connected to the common DC terminal by the resistor 30. The untagged terminal of the secondary control winding 34 is connected to the transmitter. The base of transistor 27 is the

  point of application of a triggering pulse

  to start each conduction cycle.

  The trigger oscillator that periodically powers the semiconductor switch is a second part of the operating network. This oscillator is put

  alternatively on and off and also

  frequency in response to the electrical conditions

  tributable to the electric state of the arc lamp. The oscillation

  The trip unit is also sensitive to the temperature of the switching transistor, which prevents trips.

  extended in the event of a failure of the arc lamp.

  The emitter of transistor 37 of the trigger oscillator

  It is connected to the emitter of the transistor 27, its base is coupled by the capacitor 38 to the base of the transistor 27 and its collector is connected to the node 26 by the resistor 39 and the positive temperature coefficient resistor 40. a voltmetric voltage divider (41, 42, 43); it includes the resistors 41,

  42 connected in series between the node 26 and the base of the transis-

  tor 37, and the resistor 43 connected between the base of the tran-

  sistor 37 and the common terminal of the source. During the

  temperature and operation in the final mode, where the lighting device is in the DC state (high level setting), the diode 23 is forward biased and the output voltage of the divider at the base of the transistor 37 is a direct measurement of the lamp voltage. When

  the luminaire is in high frequency conditions

  quence (on the high level of illumination setting), the diode 23 is biased in the opposite direction when the voltage

  is applied to the lamp, so that the voltage on the

  Voltage viewfinder reflects the effects of charging the lamp

  arc on the transformer circuit and constitutes a

  indirect safety of the lamp voltage. The connection of the emitter of transistor 37 to the unreferenced terminal of the

  resistance 24 in series with the arc lamp 11, makes the oscillation

  Trigger switch sensitive to the current of the lamp

  at the terminals of the resistor 24 a voltage drop proportional to this current. The trigger oscillator is connected so as to react as indicated above to

  differences between detected voltages.

  Resistance 40 with positive temperature coefficient

  (thermistor) blocks the trigger oscillator if the

  Further delay is achieved by thermally locking transistor 37 in low gain mode with moderate current saturation. The thermistor 40 is in thermal contact with the power transistor 27 and undergoes an increase in its resistance by several orders of magnitude due to

  the heating following the unduly prolonged ignition.

  Increasing the collector resistance, caused by the thermistor, reduces the gain of the transistor 37 which stops the generation of trigger pulses and imposes

  saturation to the transistor. The level of the saturated current

  is sufficient for self-heating to maintain

  hold the thermistor in its state of high resistance and

  to thermally block the trigger oscillator.

  The dimmer circuit, which supplies the filament 12

  light-reduced operation and prevents

  high-frequency operation of the operating network during

  this reduced lighting is the last part of the network

  tory. In Figure 2A it includes the components 45 to

  52 not described above and relates to the operational network

  at node 26, at the common terminal CC, at the annular contact

  7 of the base 14 and the connection between the resistors

  of the voltage divider 41 and 42 of the trigger oscillator

mation.

  The dimmer network is completed by the elements 46 to 52 which, among other functions, prevent the operation

  high frequency of the operative network during the two

  low level by blocking the operation of the oscil-

  trigger light. The remaining specific elements of the dimmer circuit are the diodes 46, 47, 48 and 52, the capacitor 49 and the resistors 50 and 51. The cathode of the diode 46 is connected to the annular contact 7 of the base 14 as well as to the cathode. the diode 45. The anode of the diode 46 is connected to the cathode of the diode 47, the anode of which is connected to the interconnection between the resistors 41 and 42 of the voltage divider of the trigger oscillator. A

  resistance 50 is provided between the node 26 and the

  between the diodes 46 and 47. The capacitor 49 is inserted

  d between the interconnection of the diodes 46 and 47 and the common terminal CC. The resistor 51 shunts the capacitor 49. The

  diodes 52 and 48 are connected in series across the terminals of the

  16. The cathode of the diode 52 is connected to the terminal

24; 72902

  positive of this capacitor. The anode of the diode 52 is

  at the same time in the annular contact 7 of the base 14 and in the

  diode 48. The anode of diode 48 is connected to the

negative terminal of the capacitor 16.

  In both low level settings, the half current

  period is applied to filament 12 through a

  taking a branch of the bridge 15 and the diode 45.-More specified-

  the switch 13 being on its first setting of

  low calf, a serial circuit is established from the driver

  white (which is not switched and is connected to one side of the

  AC) to the lower input terminal of the bridge, via the threaded part of the bushing

  17 and the screw portion 6 of the base 14. The circuit continues

  naked by the diode of the lower right position of the bridge 15 -

  anode and cathode - to the unreferenced terminal or terminal

  positive is connected to the node 26 and the cathode to the

  nular 7 of the base allows the passage of the half-period in the direction just described. The circuit continues

  the cathode of the diode 45 by the annular contacts of the

  batch and socket, the red conductor, the fixed contact 19, the rotating contact 22, and the fixed contact 18. Finally, the

  contact 18 leads to the black wire that is connected to the other terminal

  of the AC source and thus completes the power supply circuit

tion.

  On the second low level setting, an additional circuit

  is established through switch 13 between the

  black conductor and the upper entrance terminal of the bridge,

  while a switched contact of the black conductor to the catholic

  diode 45 and a non-switched contact between the

  The white source of the AC source and the lower input terminal of the bridge remain in the previous state. As for the first

  Low level setting, the filament is powered by

  half-periods through diode 45.

  In both settings at low level of illumination, the

  capacitor 16 is fed with double-state rectified current.

  nating. For the first low level setting, the diodes

  48, 52, 55 and 56 constitute a bridge which

  16 to the peak AC input potential. On the position.

  at high level, the diodes 53, 54, 55 and 56 perform the bridge rectification function. In the second low level setting, the six diodes are used with the diode 52 in parallel on 54 and the diode 48 in parallel on 53, since the pellet terminal 8 is connected to the terminal

ring 7.

  The dimmer network prevents the oscillator from

  In the case of the first low level setting, the wave resulting in the node 26 is a series of negative half-times shifted upwards so that the negative ends of this wave are approximately at the potential of the earth and that the truncated upper limits of the wave are at a positive potential of about 160 volts. The annular contact 7 becoming negative

  and the screw portion 6 of the positive pellet, the diode in operation.

  the bridge and the diode 45 are conductive.

  Since their impedance is small compared to the filament impedance, the main voltage drop occurs across the filament and the voltage at the terminal of the filament

  filament connected to the node tends to zero. At the same time, the former

  negative section of the annular contact 7 makes the diodes 46 and 47 conductive which brings the upper grip of the

  voltage divider 41, 42, 43 connected to the base, the potential

  tiel of the earth. Thus, the charge of capacitor 49 is

  at a potential close to that of the earth. In the same

  At the same time, the diode 47 which connects the capacitor to the upper tap of the voltage divider 41, 42, 43 stabilizes the

  this potential near zero potential which ensures

  re blocking of the oscillator transistor. During the

  half-period, while the voltage on the annular contact

  becomes positive with respect to the voltage of the screw part, the diode 45 is polarized in the opposite direction and the

  node 26 reaches its maximum positive value (+ 160 volts).

  During this half-period, the diode 46 leading to the condensation

  49 is also polarized in the opposite direction and prevents

  the capacitor to be positive on node 26 and the cir-

  resistant foods established by resistances 50 and 41 (

  through the diode 47) allow charging and,

  consequently, to gradually increase the voltage at its

  nes. The charging time constant is chosen quite

  to ensure the continuous blocking of transistor 37 of the os-

  during the entire half-period. With the

  their indicated, the d.d.p. on the capacitor increases

  than 16 volts, while the voltage on the

  The higher the voltage, the higher the voltage drop in a diode. The voltage on the lower tap connected to the base of the transistor is equal to the voltage on the upper tap divided in a ratio of 1 to 30 set by the resistors 43 and 42, respectively. Thus, the voltage remains below about half a volt

  the entire cycle and is insufficient to polarize posi-

  the transistor 37. When the negative excursion is

  the diodes 46, 47 become conductive once again.

  and discharge capacitor 49 to near zero and repeat the cycle just described. In the second low setting, the process is almost the same as the one above. With the indicated values, the blocking is maintained and the trigger oscillator remains inactive; accordingly, the switching transistor

  27 remains in the normal state of non-conduction.

  The suppression of trigger oscillations

  without any adverse effect on the functioning of the

  lighting when the setting is on the high level.

  In other words, the oscillation suppression circuit has no adverse effect on the ignition or the reignition or on the maintenance function of the arc, ensuring the arc immunity sector transients. Anti-interference is achieved without expensive mechanical or electrical devices and

  only requires the simple circuit elements described here.

  The suppression of the parasites is essentially carried out by the diode 47 so the reverse bias is maintained and which ensures the decoupling of the capacitor 49 from the

  basic voltage divider during all modes of operation

  significantly with the high level setting.

  When the voltage is applied for the first time with

  this setting, the capacitor 49 is at an initial potential

  tial low and prevents, from the outset, the operation of the trigger oscillator. However, the capacitor

  load quickly, usually in 50 milliseconds,

  a value allowing the initiation of oscillations in the os-

  trigger sparkler. In the remainder of the ignition process, the trigger pulses being generated periodically and the transistor switch 27 also operating periodically, the node 26 alternately switches to

  a high positive potential and a potential close to zero.

  The capacitor 49 charges through the resistor 50 and

  sometimes through the resistance 41 up to an average value

  depending on the utilization coefficient but less than the peak value applied to the node 26. The diode 47 thus isolates the capacitor 49 of the node during the time when the switching transistor is in operation and a part of the time when it is off with a voltage not exceeding

  not yet the one that the capacitor stores 49. This iso-

  and the high value of resistances 50 and 51 in

  charging circuits reduce the intensity through the conden-

  49 so that there is no significant reduction in

  the ignition energy of the arc lamp. The circuit did

  nor does it have a significant effect on the frequency of

  of the arc lamp since the frequency of

  petition is determined primarily by the weak (1k)

  resistance 43-and the capacitor 38. Assuming that the lamp

  arc has reached a normal steady-state voltage which

  gives about 90 volts at node 26, the capacitor

  to a value set by the ratio between the resistors 51, that is to say one third of 90 volts, ie 30 volts, which makes it possible to use an electrolytic capacitor of

volts, relatively inexpensive.

  The maintenance characteristic of the bow is not affected

  by the trip suppression circuitry. The trend

  capacitor 49 sets the voltage on the capacitor

  At the same time, the anode of the diode 47 is connected to a similar tap on the voltage divider circuit 41, 42. At this tap, the divider ratio is one fifth of the voltage at the node. 26 and, assuming that

  the node is at 90 volts, the diode is polarized indistinctly

  poured by about 12 volts during operation in mod-

  of normal. Thus, assuming a voltage variation on the voltage divider or the current in the arc lamp, the input bias on the transistor 37 of the trip oscillator remains unchanged by the presence of the

  capacitor 49 or other components used to

  prime the trigger oscillations. In short, the character

  maintenance of the arc is not impaired.

  The pair of diodes 48 and 52 is provided to protect the lighting device against both high voltage transients and ignition overvoltages, in particular

  in the first position at low level.

  The transient protection in the high level position and the second low level position is due to the presence of the bridge and the capacitor 16. The diodes 52 and 48 shunt the filter capacitor 16 and their

  point of interconnection is connected to the annular contact 7

  describes me above. Protection is provided primarily

  for periods when the switch is in the second position

  but because of contact problems, can also be active in the fourth position if contact with

pastille is mediocre.

  The principle of protection is to evacuate all over-

  sector without damage through a diode with low impedance

  in the capacitor of 50 microfarads 16. The diode 52 provides protection against positive overvoltages on the annular contact by uncoupling them to the capacitor through its positive terminal; diode 48 similarly protects against negative transients in the sector,

  decoupling them to the capacitor 16 by its negative terminal.

  Some inexpensive diodes have very low current limits

  and their use with a large capacitor for

  absorbing the load prevents the application of currents or

  significant transients to other elements of the

  cooked. The ignition overvoltage protection is provided by the diode 48 which is shown connected between

247 2902

  the annular contact and the common terminal of the DC power supply. If, for reasons of economy, we want to eliminate the transient protection circuit of the

  present embodiment, diode 48 would remain in the

  2, or at node 26 to prevent the latter from being rendered negative by the ignition overvoltage. (The second embodiment which will be described with reference to FIG. 4A is thus devoid of protection measures against transients of the sector). One of the adverse consequences of the transition to a negative potential of the node 26 is the application of a reverse voltage on the small capacitor of 2.2 microfarads 49 and the passage of a

  excessive current in the output junction of transistor 27.

  The condition in which the node is made negative exists

  when the lighting device is put into operation the first

  first time, normally on the first low level setting.

  The critical period is the first moment after power up, when the capacitor 16 starts charging at a positive value. The overcurrent is determined by the AC-sector impedance, the series junction elements, and the 2 ohm 24 series resistance across the AC sector. A maximum overcurrent of 50 amps could be considered, but a value of 10 amps is more normal given the other elements in series. Assuming 10 amps overcurrent, the voltage drop across the 2 ohm resistor would be 20 volts negative relative to the circuit ground (in the absence of diode 48). This voltage, minus the collector-base forward voltage drop of transistor 27, would appear at node 26. Since diodes 45 and 46 are also

  conductors, this tension would also be found in

  Thus, the presence of the diode 48 (in either position) prevents negation of the node 26, and in turn, the normally positive electrode.

  capacitor 49. The presence of the diode 43 avoids

  re call for a capacitor supporting the alternating current and allows the use of an electrolytic capacitor

  for relatively low voltages, as previously described.

  With regard to the transistor 27, the diode 48 (in

  one or the other position) protects it from the same strong surin-

  Tensity that occurs when the capacitor 16 is charged for the first time. Starting at the reference or ground terminal, the circuit taken by the current through the

  transistor can be considered as supplemented by resistance

  24, the windings 33, 34, the base and the collector, respectively, of the transistor 27, the node 26, the diode 45,

  through the annular contact connection 7 (socket and socket)

  1) and the screw-in portion 6 (where the AC generator supplies 120 volts), the fuse, the lower right diode of the bridge 15, the positive terminal of the capacitor 16, the other terminal of which is grounded. The polarities of the diode 38, connected between earth and annular contact 7

  (the diode 45 being conductive) is between node 26 and ter-

  re, are the same as those of the output junction of transistor 27; the diode 38 is connected in parallel to the part of the circuit which has just been described and which comprises the resistance of 2 ohms 24, the windings 33 and 34-, the base and the collector, respectively, of the transistor 27. At

  beginning, when the node 26 becomes negative because of the

  initial intensity in capacitor 16, most of

  current between transistor 27 and diode 48 is

  by the transistor since its junction surface is large compared to that of the diode 48 and being

  given that at low intensities the effect of the fall in

  in the 2 ohm resistor 24 is negligible to derive the overcurrent on diode 48. Overcurrent

  increasing, the potential difference across the boundary

  added resistance to the voltage of the output junction of the transistor is greater than the voltage drop in the junction of the smaller diode 48. When this occurs, a significant fraction of any overcurrent is derived by the diode 48 and spaced apart from the output junction of the transistor 27, which avoids being subjected to too much intensity. A relatively low cost diode can

  resist overcurrents of dozens of amps

  without damaging effects and thereby protect ef-

  fectively the transistor that can not tolerate them in the

same proportions.

  To switch to the second low level setting from the high level setting, it is necessary to turn off the arc tube. This is done by the diode 45 (when the annular terminal 7 becomes negative) which withdraws the current of the arc tube for a long enough time to achieve its extinction, and by the diode 47 which withdraws the base current of the transistor 37 of the oscillator, thus putting out of service

  the transient trap system that could otherwise

  ter to maintain the ionized arc tube.

  Figure 4A is similar to Figure 2A except for the dimmer circuit. In FIG. 4A the dimmer circuit comprises the components 60 to 63 which are connected in the circuit to the node 26, to the transistor 27, to the annular contact 7 and to the pellet contact 8. The anode of the thyristor

  (SCR) 60 is connected to the node 26, its cathode in contact with the

  lot 7, and its trigger at the junction of a resistor 61 and

  of a capacitor 62 connected in series between the annular contact

  7 and the pellet 8, as shown in the figure.

  A diode 63 is also provided whose anode is connected to the node 26. The cathode of the diode 63 is connected to the collector of the transistor 27 and to the upper end of the resistor

  with positive temperature coefficient (PTC) 40.

  The circuit of Figure 4A operates in the same way.

than that of Figure 2A except for the gradual

  which operates as described below. The community

  tator 13 being on its second position (light level

  low), a half-period current is applied to the

  12 through the thyristor 60 which is "turned on" by the trigger during these half. periods thanks to the current

  through the capacitor 62. The diode 63 prevents the conden-

  filter 16 to charge at a sufficient potential

  high to operate the trigger oscillator 37

  during this level of low illumination.

  In the third position (high level) of the switch,

  the annular contact 7 is not connected to the input of the

  Therefore, the thyristor is "off" and the arc lamp operates as described above. In the fourth position of the switch 13 (high level) the annular contact 7 and the pellet contact 8 are connected to each other and put the resistor 61 and the capacitor 62 in parallel, polarizing the thyristor to the state " off ". The operating network shown in FIGS. 2A and

  4A and not including the measures associated with the

  dimmer is covered by the patent application of the

  United States of America serial number 47.972. The description

  following is extracted from this patent application and is

  born so that the demand and the benefits are well understood

concerning the present invention.

  During pre-boot, boot and transition

  between glow discharge and arc (with the setting on ni-

  calf), the transformer 23, the transistor switch

  tor 27 and the trigger oscillator (37, etc.) of the

  operating bucket play an active role in generating a

  high frequency output. The modification of the electrical output

  which occurs between the glow discharge transition-

  cente + arc and the rise in temperature is a reaction to

  existing conditions in the main lamp. Modifications

  more gradual effects of the electrical output of the

  occur between pre-priming and priming and

  between priming and the transition between glow discharge

  te and arc; they are also a reaction to the conditions

existing in the main lamp.

  During pre-initiation, priming and transition to

  glow discharge and arc, the operating network pro-

  high-voltage pulses of short duration for

  the arc lamp is bridged, the voltage falling to a lower value in response to the lamp charge during the transition between glow discharge and arc. During pre-initiation, the unidirectional high-voltage pulses exhibit significant undamped oscillations and are produced at the rate of 50 kHz. During the transition between glow discharge and arc, the undamped oscillations are reduced and the frequency goes to 35 kHz. The shift

  towards a lower frequency produces a factor of

  the transistor in conduction, which increases

  the energy supplied to the lamp during the transition between

  luminescent charge and arc. The operating network also feeds the resistive filament 12 in the form of a series of unidirectional pulses at the frequency

50-30 kHz.

  The operating network produces electrical excitation

  high frequency described above as a result of the switching

  high-frequency operation of the monostable switch

  tor. The intermittent switching of the switch to

  tor produces an AC component in the primary primary winding 31 of the step-up transformer, an alternating component that is boosted at the output of the transformer

  and a pulsed current in the resistive filament 12, essentially

unidirectional.

  The alternating current in the primary winding

  cipal is produced in the following way: suppose the

  transistor 27 has been activated by a signal of

  appropriate clipping applied at its entrance junction; a

  current circuit is completed between the

  not positive and the common terminal of the DC power supply.

  Switching transistor offers low impedance

  when it drives and the capacitor 35, the primary winding

  reaction 33 and resistance 24 are also low

  impedance. The current increasing in the. circuit, wind it up

  The primary reaction element, which is inductively coupled to the secondary feedback winding 34, produces a feedback on the input circuit of the transistor and makes it even more conductive. However, the increase in current continues until a predicted flow level is reached in the

  core of the power transformer. At this point, the

  tion reverses to become a feedback and turns off transistor 27 before the core has reached

  complete saturation. Transistor 27 is no longer conductive

  the circuit established for the passage of the current in the primary winding is open and a part of the energy

  stored in the circuit can dissipate in the form of

  Inverse filament in the resistant filament 12.

  Transformer 28 has the characteristic of

  pour the reaction and turn off the transistor before the core has reached full saturation. This transformer is illustrated in Figure 3 which shows the

  double-core E or 8-core structure with an ori-

  this control at the base of the central branch formed by the bars of the "E". The main power windings

  31 and 32 are shown wound around the central branch

  corresponding to the bars of the E, while the

  Primary and secondary control bearings 33 and 34 are wound through the orifice. The meaning of the reaction depends

  the level of flow in the core surrounding the orifice. The neck-

  The reactive range at the secondary control winding 34 is reactive at low flux levels and at negative feedback.

at high flow levels.

  The transformed version of the alternating voltage

  the frequency available across the primary winding during pre-priming, priming and transition between

  glow discharge and arc appears at the coil terminal

  32 the output is coupled from the winding 32, by means of the capacitor 36, to

  the anode of the arc lamp 11. The output takes the form of

  unidirectional pulses thanks to the presence of the diode

  23 whose anode is connected to the node 26 and to the terminal

  peeped by a point of the second winding and whose cathode is connected to the anode of the arc lamp. The polarity of the diode 23 is intended to allow the application to the arc lamp of a high voltage at the secondary, developed during

  the passage of the direct current when the communication transistor

  tation is conductive. Transformer 28 is a transformer

  voltage booster having a conversion ratio

  640/140 and which, given the polarity given to the diode 23, supplies energy to the arc lamp during

  the periods when the transistor switch is off.

  With the parameters indicated, and in the hypothesis of oscilla-

  In the case of large unmortized voltages, the pre-priming potential available is 1600 volts peak-to-peak. The nominal duration

  pre-prime is zero when the lamp is cold

  of; it is between 45 seconds and 4 minutes when

the lamp is hot.

  Auxiliary lighting current during pre-priming

  Ge, priming and the transition between glow discharge and arc is produced by the high frequency switching of the transistor switch. At the moment when the transistor switch becomes conductive, a circuit for the direct current is completed between the positive and common terminals.

  DC power supply. The circuit CC comprises the filament

  12, the transistor 27 (collector and emitter)

  respectively), the primary winding of reaction 33 and the current-sensing resistor 24. The transistor 27 has a low impedance when it is conducting and the impedances of the primary winding of reaction 33 and

  resistance 24 are also weak.

  In addition to the intermittent current applied to the filament

  the circuit that has just been described, the part of

  return of the alternating current passing through the primary winding

  Mayor 31 of the transformer also passes through the resistant filament as explained above.While pre-priming,

  the secondary winding of the transformer 28 being practically

  in an open circuit, the thermal effect of the reverse current

  in the primary circuit is negligible. During the transi-

  between discharge and arc, while the lamp absorbs the

  more energy, the alternating current adds an important

  aunt to the total dissipation in the filament, in which

  pulsed DC excitation is reduced.

  Since the setting is on a high level of illumination, the

  operating bucket is sensitive to the electric state of the arc lamp in order to produce the outputs described previously,

  during pre-priming, priming and transition period

  between discharge and arc. The means by which this feeling

  sibility is achieved comprises the tripping oscillator (transistor 37, etc.), the detector resistance of the lamp current 24 and the voltage detecting resistors 41, 42

and 43.

  The trigger oscillator causes the operation

  active state of the transistor switch 19 during the pre-

  priming and the transition period between discharge and arc

  and controls the duty factor of the transistor for

  add additional energy to the arc lamp during the transition period between discharge and arc. The switch

  transistor being monostable each trigger pulse

  provided by the trigger oscillator initiates a conduction sequence. If it is desired that the arc lamp does not work at all, such as when the light fixture is on a low level setting and only the illumination by

  the filament is desired, it is necessary, in accordance with

  that high-frequency operation is prevented,

  by suppressing the oscillations of this oscillator. The function

  gradation, as mentioned above, guarantees the flexibility

  power supply response to rapid changes in lamp voltage and current, or overcurrent and

surges in the sector.

  With the setting on the high level of illumination, the os-

  trip generator is activated when the operating network is excited for the first time and

  remains excited for the duration of pre-priming,

  bracing and the transition between discharge and arc. During pre-priming, no current flows through the lamp, while during priming and transition from discharge to arc, the lamp current increases to a fifth peak ampere in short pulses. The tension that

  originates in the primary winding of the transforma-

  at node 26 is high (> 300 V) during pre-priming, drops substantially under the load effect of the lamp during priming and the transition between discharge

  and arc, and consists of a series of pulses accompanied by

  at the origin of significant unmortized oscillations.

  The above-mentioned intensity and voltage conditions, reflecting the state of the lamp during pre-priming and the transition between discharge and arc, are perceived in the operating network and differentially combined at the junction.

  input of the trigger transistor. Any current of lam-

  passing through the lamp current detection resistor at which the emitter of the junction transistor 37 is coupled by the low impedance reaction winding 33, produced

  a voltage whose direction tends to polarize

  pour in the entrance junction. (The current in the lamp is zero at the beginning and remains low during the aforementioned conditions of the lamp). The voltage at node 26 is applied to

  terminals of the voltage divider (41, 42, 43) whose internal

  The voltage appearing at node 26 is positive and a fraction (1/181) of this voltage is applied to the base. Here, the direction of the current tends to polarize in a forward direction the input junction. During pre-initiation, the voltage at node 26 is maximum and sufficient-assuming that the capacitor

  33 had the time to charge-to polarize in the direction of

  Rect the transistor 37 and trigger the oscillation.

  The trigger oscillator works like an os

  the relaxation capacitor 38, the capacitor 38 being loaded

  periodically through the passive components of the operational network.

  and periodically discharged by the transistors 27, 37. The charging time of the capacitor 38 is determined

  mainly by its own value, the value of the resistance

  43 and the differential voltage used for the

  ger. The breaking action of the transformer 28 leaves a residual inverse voltage across the capacitor at the end of the conduction of the switch, limited by the diode 29

  and the resistor connected in series.

  As seen by examining the circuit, when the node 26 is the seat of sufficiently high potentials, and assuming a weak lamp current, the oscillator

  starts driving when the capacitor 38 reaches the

  their necessary to the polarization in the direct sense of the

  input voltage of transistor 37 (+ 0.6 volts), as shown

  upper. The voltage across the capacitor is determined

  born by the difference between the voltage at the lower tap of the voltage divider and the voltage due to the lamp current

through resistance 24.

  Once transistor 37 is conducting, the

  rant passes through the primary reaction winding 33 and the strong reaction due to the secondary reaction winding 34

  and capacitor 38 produces a short circuit during the

  triggering pulse to activate the switching

transistor transistor 27.

  Assuming that the current of the arc lamp has started to flow and that the voltage across the lamp

  has begun to increase, the differential voltage used

  to charge capacitor 38 falls back to average,

  increasing the time required to make the

  sistor 37 driver and start the trigger pulse

  next. This allows more time to apply to the

  eg the energy stored in the input circuit of the

  tory. Earlier in the ignition cycle, the

  The cathode rant of the lamp can be truncated by

  following conduction value and a lower amount of

  stored energy is supplied to the arc lamp. The circuit has been designed so that the non-conduction time is maximum when the voltage across the lamp is in the discharge zone (approximately 200-400 volts) to

  the output power (at approximately 9 watts) of the

metal vapor pumps.

  The setting is on high level, once the lamp

  arc has reached the corresponding thermo-ionic

  As the temperature rises, the high frequency output

  transistor switching is designed for these

  ser and the CC state begins. The trigger oscillator, which activates the monostable transistor switch, remains polarized in the opposite direction as a result of a new game

  conditions of currents and voltages in the network operated

  and becomes inoperative. The high frequency voltage

  presented at node 26, previously applied to

  to the voltage divider 41, 42, 43 is replaced by a constant DC voltage having a certain ripple and constituting the voltage of the lamp. The DC voltage remains in a direction favoring the conduction, but is 1 or 2 orders of magnitude lower. The diode 23, polarized now

  in the forward direction, connect the voltage divider to the terminals

  of the lamp and this divider then detects 1/181 of the

  new lamp voltage, 15 volts at the beginning. simul-

  a maximum initial lamp current of 6/10

  amp, goes through the resistor 24 and creates a voltage drop.

  anti-conduction ratio of 1.2 volts. Differential voltage polarizes the switch input junction in the opposite direction

transistor.

  The rise in temperature continuing until the condition

  final run, the lamp voltage increases and the

  rant that passes through it decreases. The state detectors of the

  lamp are determined for the oscillator to trigger

  It remains inoperative throughout the temperature rise and the final run. In the final mode, the lamp reaches a current of 0.3 amperes and a voltage of 87 volts. If this voltage exceeds the normal values by 10 volts (eg 97 volts) and the current drops to 0.050 amperes, the trip oscillator resumes operation and

  thus constitutes a security against the fallout of the transis-

tor.

Claims (10)

R E V E N D I C A T I 0 N S   1 - Lighting device for operation on cou-   alternative, with light level   low and high, characterized by the combination of: a) first, second and third   (6, 7, 8) for the selective connection of the illuminating device   AC source, b) a rectifier bridge (15) having first and second AC input terminals, and first and second DC output terminals, the first input terminal of the bridge being connected to the first one; terminal (6) of the lighting device and the second input terminal of the bridge being connected to the second terminal (8) of the lighting device,   c) a first filter capacitor (16) connected   the above-mentioned DC output terminals,   (d) a main arc lamp (11) connected in a cir-   bake series between a node (26) and the first output terminal   to provide a high level of illumination   and asking for an excitation depending on his or her elec- cudgel,   e) a resistant filament (12) connected in a separate circuit   between the second output terminal of the bridge (15) and the node (26), the filament providing low intensity illumination with the low level setting and auxiliary illumination with the high level setting during the illumination of the lamp main and a ballast circuit for the   current of the main lamp (11) during operation in the final regime,   f) an electrical transformer (28) having a winding   primary element (31) connected in a series circuit between the   x the bridge output terminal and the node (26), and a second winding (32) connected in a serial circuit between the node   mentioned above (26) and a first of the terminals of the main lamp blade (11),   g) a first diode (23) connected in a separate circuit   between the node (26) and the first terminal of the main lamp (11) with a polarity allowing the passage of the current of the main lamp through the filament (12),   and in parallel on the second winding (32) for the re-   establishment of the transformed potentials which appear at its terminals,   h) a semiconductor switch, monostable, normally   Non-conductive element, comprising a first transistor (27)   connected in a series circuit between the node (26) and the first   bridge exit terminal (15) already mentioned, the function of which   intermittently produces a pulsating current in the filament   (12) to obtain the auxiliary lighting, a voltage   in the primary winding (31), rectified by the aforementioned diode (23) and applied to the main lamp (11) for its ignition, i) a rectifier- (45) connecting the node (26) to the third terminal (7) of the following lighting device   a polarity allowing the conduction of half-periods through   towards the rectifier bridge (15) and the filament (12) for   light, the setting being low, and   j) means (46, 4, 9) for holding the semiconductor switch   driver in the state of non-conduction when the setting is on low level.   2 - lighting device according to claim 1 characterized in that it further has: k) a trigger oscillator sensitive to the electric state of the main lamp (11) to cause the   intermittent operation of the switch in order to   mage of the main lamp, and comprising: 1) a second transistor (37), with base, emitter and collector connected in an oscillating configuration, 2) a resistance voltage divider (41, 42,   43) connected in series between the node (26) and the first terminal   an output of the bridge (15) for producing a voltage drop proportional to the current in the main lamp (11), and   4) a means of connecting the base of the second tran-   sistor (37) at a tap of the voltage divider (41, 42, 43) for the detection of the voltage across the arc lamp (11) and other connection means (33) of the transmitter of this   second transistor (37) to the other terminal of the lamp for   the current passing through it, and characterized in that   L) means for maintaining the semiconductor switch   driver in the state of non-conduction includes a means   maintaining the trigger oscillator in a condition   non-oscillating when the setting is low, in particular: 1) a second diode (46) connected in the series circuit between the third terminal (7) of the lighting device   and the voltage divider (41,42,43) having its cathode   connected to the third terminal and its polarity intended to reduce the potential of the aforementioned base by reference to that of the   first output terminal of the bridge (15) in order to avoid the   by the second transistor (37) during half periods o the rectifier leads, and   2) a second capacitor (49) connected between the anode   of the rectifier device (45) and the first output terminal   of the bridge (15), the second capacitor (49) maintaining the reduced potential on the base to prevent conduction in the second transistor (37) during the half-periods o   the rectifier (45) is not conductive.   3. Lighting device according to claim 2,   characterized in that the means for maintaining the trigger oscillator in the non-oscillating state comprises:   a third diode (47) inserted between the device   tif rectifier (45) and the voltage divider (41, 42, 43),   the cathode of this third diode (47) being connected to the   node of the second diode (46) and its anode at the divider of   voltage, the third diode (47) preventing, when the   ge is on low level, the voltage at the connection to the divider become much more positive than the voltage reduced on   the second capacitor (49), in order to suppress oscillations triggers.   4. Lighting device according to claim 3   characterized in that a second resistor (50) is provided,   connected between the node (26) and said terminal of the second con-   densifier (49) to charge this second capacitor to a   value which ensures the polarization in the opposite direction of the se-   diode (46) and the decoupling of the second capacitor (49) 2A72902   of the voltage divider (41, 42, 43) while the setting is high level for immediate response to conditions of the arc lamp (11).   Lighting device according to claim 4, characterized in that a third resistor (51) is provided   shunts the second capacitor (49), the ratio of the two   x (50) and third (51) resistors being greater than the dividing ratio of the voltage divider (41, 42, 43) so   to maintain polarization in reverse on the third   diode (47) during operation with the high level setting, the second and third resistors (50, 51), reducing the voltage on the second capacitor (49) in   an inverse proportion to this ratio.   6 - Lighting device according to claim 5,   characterized in that a fourth diode (48) is provided,   between the node (26) and the first output terminal of the   bridge to prevent voltage inversion at the node (26),   the inversion of the voltage across the second   (s) (49) and reduce the intensity of the semiconductor switch too much during the initial charge of the first capacitor (16), normally when the   is on the low level of illumination.   7 - Lighting device according to claim 5,   characterized in that: - a fourth diode (48) is connected between the third terminal (7) of the lighting device and the first output terminal of the bridge to prevent voltage reversal   at the node, prevent voltage inversion across the se-   cond capacitor and reduce the intensities too strong on the semiconductor switch during the initial charge of the first capacitor. (16) normally when the setting is on the low level of illumination.   8 - Lighting device according to claim 7, characterized in that   a fifth diode (52) is provided, connected to   the first output terminal of the bridge (15) and the third terminal (7) of the lighting device which, in cooperation with the fourth diode (48) provides protection against transients of the sector, of positive or negative polarity, when the setting is on the low level of illumination and only the first and third terminals of the device   lights are connected to the AC source.   9 - Lighting device according to claim 8,   characterized in that it is adapted to allow adjustment   generating successively low, high and low illumination levels when inserted into a three-way switch socket (17) (18), this lighting device   being provided with a base (14) fitting on the sleeve three-   channels (17) and comprising a cylindrical base contact   let (6) defining the first. terminal of the apparatus of   lighting, a patch (8) arranged at the center of the end   of the base and constituting the second terminal of the apparatus of   lighting, and a ring (7) encircling said pellet and   constituting the third terminal of the luminaire.   - A lighting apparatus for AC operation having low and high illuminance level settings, comprising:   (a) a first (6), a second (8) and a third   (7) terminals for the selective connection of the   lighting source to a source AC, b) a rectifier bridge (15) having a first and   a second AC input terminals and a first and a second   of DC output terminals, the first input terminal of the bridge   being connected to the first terminal (6) of the device   lighting, and the second terminal of the bridge being connected   at the second terminal (8) of the lighting device, c) a main arc lamp (11) connected in a series circuit between a node (26) and the first output terminal, to provide a high level of illumination. illumination and requesting excitation according to its electrical state,   d) a resistant filament (12) connected in a circuit   baked series between the second output terminal of the bridge and the node (26) the supplying filament, when the setting is   on the low level, low intensity lighting and   that it is on the high level a ballast circuit for the   current of the main lamp after ignition.   e) means (28) for lighting the main lamp   when the setting is high; and f) means for connecting the node (26) and the third terminal (7) of the illumination device for excitation of the filament for illumination when the adjustment ge is on low level.   11 - Lighting device according to claim 10, characterized in that the connecting means of the node (26) to   the third terminal (7) of the lighting device is a diode   polarity connector (45) for energizing the filament (12) by half-periods through said rectifier bridge (15),   when the setting-is on low level.   12 - Lighting device according to claim 11,   characterized in that the ignition means of the main lamp   blade (11) is connected to the DC output terminals and comprises a step-up electrical transformer (28) and a semiconductor switch operating intermittently to apply a high ignition voltage.   13 - Lighting device according to claim 12, characterized in that the step-up transformer (28) and the   semiconductor switch operating intermittently   they are connected to the node (26) in order to apply a current   pulsed to the filament (12) to provide auxiliary lighting during ignition.   14 - Lighting device according to claim 10, characterized in that the means of connection to the node (26) of   the third terminal (7) of the lighting device is a thy-   ristor (60) whose polarities allow the excitation of the filament (12) by half-periods through the bridge rectifier   (15) when the setting is low, the anode of the thy-   ristor being connected to the node (26). the cathode to the third   terminal (7) of the lighting device and the trigger   terminal (8) of the lighting device.