US3872319A

US3872319A - Lazy-man type switching circuit

Info

Publication number: US3872319A
Authority: US
Inventors: Jr George E Platzer
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-07-31
Filing date: 1972-07-31
Publication date: 1975-03-18
Anticipated expiration: 1992-03-18

Abstract

Circuits and apparatus are provided for the control of a lamp from either a wall switch or a second switch located at or near the lamp, in such a way that the lamp may be turned on or off independently from either switch.

Description

United States Patent [191 Platzer, Jr. I 1 1 Mar. 18, 1975 [54] LAZY-MAN TYPE SWITCHING CIRCUIT 3,496,379 2 1970 Platzer 307/114 [76] Inventor: George E. Platzer, ,lr. 31881 OTHER PUBLICATIONS Staman Farmmgto Hllls- Mlch- Zarr, Build a Carrier Current Remote Control Sys- 48024 tem," Popular Electronics, January, 1967, pp. 50-53. [22] Fil d; J l 31, 1972 Bik, Build The Dynadim, Popular Electronics, Sept.

1968, pp. 71-73. [21] Appl 276539 GE Remote Control System, 1952, page 11.

' R. A. D'Arche. Two Location Control, Popular [52] US. Cl. 307/114, 317/157 Electronics, Oct. 1967, p. 14. [51] Int. Cl. H0lh 31/10 [58] Field of Search 307/140, 114; 317/157; Primary Examiner-Robert K. Schaefer 34 /1 7 l5/DIG. 4 Assistant Examiner-William J. Smith [56] References Cited 57 T C UNITED STATES PATENTS Circuits and apparatus are provided for the control 01' 941,777 11/190 H t 307/114 a lamp from either a wall switch or a second switch 2.835.830 5/1958 Rathem u 1 307/114 located at or near the lamp, in such a way that the 334881669 5/1959 f 317/54 X lamp may be turned on or off independently from ei- 3,334,250 8/1967 Gwm 307/114 ther switch 3,418,488 12/1968 Platzer 307/114 3,418,489 12/1968 Platzer 307/114 15 Claims, 13 Drawing Figures FTJENTEU HAR I 8 ESTS SHKU 2 [IF 6 PATENTED 3.872.319

sum 3 0r 6 HARI aims 872.31 9

sum u or 5 1 LAZY-MAN TYPE SWITCHING CIRCUIT BACKGROUND OF THE INVENTION For many years, homes have been built without ceiling and wall lighting fixtures. In such homes it is still necessary to provide the dweller with a way of lighting a room before entering it. This is done by having a wall switch near the room entrance which controls one or more of the wall outlets in the room. It is intended that a lamp be plugged into the switch controlled outlet.

Unfortunately, this creates problems. For example, in a bedroom the lamp is best placed by the bed. In this case the lamp is turned off, upon retiring, at the lamp. The next morning, the lamp probably will not be turned back on again because of the daylight. The next night, the lamp cannot be turned on by the wall switch since the lamp was turned off by the lamps switch. This is not only annoying, but it is also dangerous, because a person is then forced to enter a dark room.

SUMMARY OF THE INVENTION This invention is directed to a lamp as well as circuits and apparatus, therefore, which enables the remote operation of the lamp. The circuits and apparatus allowthe lamp to be turned on or off independently from either a wall switch controlling a wall outlet or a second switch located at or near the lamp. In general, the power to light the lamp is taken from a wall outlet that is continuously energized. The power from the wall outlet controlled by the wall switch is used only to operate a relay or the gate circuit of a solid state switch. The circuitry disclosed will function properly even if the two outlets employed provide voltages which are not in phase.

Several different packaging arrangements for the circuits are used. Two are designed for use with ordinary lamps, and would be classified as adapters. Another arrangement shows the circuitry built into the lamp.

Hence, a general object of this invention is to provide circuitry and apparatus for the independent control of a lamp from either a wall switch or a switch at or near the lamp, regardless of the phase of the wall outlets used.

Another object of this invention is to provide a lamp which does not require the use of an adapter for independent control from two switch stations.

Still another object of the invention is to provide improved adapter means for converting a standard lamp to one that may be turned on or off independently from two switch stations.

DESCRIPTION OF THE DRAWINGS In the drawings, wherein for purposes of clarity certain elements and/or details may be omitted from one or more views:

FIG. 1 is a perspective view of a table lamp operable independently from either the wall switch or the lamp switch;

FIG. 2 is a schematic wiring diagram of a circuit employable with the lamp of FIG. 1;

FIG. 3 is a modification of the arrangement shown in FIG. 1;

FIG. 4 is a partial view showing a modification of FIG. 3;

FIG. 5 is an enlarged view of one of the elements shown in FIG. 4;

FIG. 6 is a schematic wiring diagram of the circuit employable with the arrangement shown in FIG. 4;

FIG. 7 is a perspective view of an adapter embodying the teachings of the invention;

' FIG. 8 is a schematic wiring diagram employable with the adapter of FIG. 7;

FIG. 9 is another adapter embodying the'teachings of the invention;

FIG. 10 is a schematic wiring diagram of a circuit employable with the adapter of FIG. 9;

FIG. 11 is a schematic wiring diagram of a circuit employing a thyristor to turn an associated lamp or other load on and off;

FIG. 12 is a schematic wiring diagram ofa circuit employing a pair of thyristors to turn a lamp on and off; and

FIG. 13 is a schematic wiring diagram of a lamp switching circuit incorporating a lamp dimmer control.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, FIG. 1 shows a perspective view of a lamp 10 connected by a cord 12 and a plug 14 to a continuously energized outlet 16. The lamp is also connected by a cord 18 and a plug 20 to an outlet 22 which is controlled by wall switch 24. A switch 26 is shown on lamp l0.

Switches

24 and 26 permit light bulb 28 to be turned on or off independently from either switch.

Outlets

16 and 22 may be what is commonly referred to as a duplex-type outlet assembly which for purposes of definition herein shall mean any such multiple outlet assembly which has two or more outlets therein. Switch controlled duplex-type outlets are sometimes wired so that both outlets in the pair are simultaneously energized and de-energized by the wall switch. Sometimes they are wired so that one of the outlets is continuously energized and only the other outlet is controlled by the wall switch.

FIG. 2 is a wiring diagram of the circuit for use with the arrangement of FIG. 1. Like elements in FIGS. 1 and 2 are designated by like numbers. A source of alternating electrical potential 30 has

output terminals

32, 34 and 36. Terminal 36 is indicated as being grounded. Source 30 could be the windings ofa generator, but it may equally well be the secondary windings ofa distribution transformer which serves, for example, several nearby homes. Such a distribution transformer usually has a 220 V secondary which is center tapped. The center tap depicted by terminal 36 is grounded. Relative to terminal 36,

terminals

32 and 34 are at a potential of V, but obviously the 110 V lines are degrees out of phase. The 220 V appears between

terminals

32 and 34. In general, both llO V lines are wired throughout a house with the loads distributed as evenly as possible on them. It is possible to have both 1 10 V lines supplying different wall outlets in the same room, and FIG. 2 shows this case.

Conductor 38 connects terminal 32 to switch 24. A conductor 40 connects switch 24 to a femal receptacle 42. A conductor 44 connects terminal 36 to a female receptacle 46.

Receptacles

42 and 46 comprise one of the outlets 22 in FIG. 1. Conductor 48 connects terminal 34 to a female receptacle 50. Conductor 52 connects conductor 44 to female receptacle 54.

Receptacles

50 and 54 comprise one of the outlets 16 in FIG. 1.

ductors

60 and 66 comprise cord 18 of FIG. 1.

Electromagnet 64 is mounted inside lamp assembly which in FIG. 2 is generally designated by phantom line 70. Associated with electromagnet 64 is a single pole double throw switch 72 which comprises double fixed contacts and an armature 76. Magnet means 64 and 72 comprise a relay 71. A resilient element 74 hiases armature 76 of relay 71 against a normally closed contact 78. Contact 80 is the normally open contact of the relay 71. A conductor 82 connects the armature 76 of the relay 71 to a terminal 84 of light bulb 28.

Male prongs

86 and 88, shown engaged with

female receptacles

50 and 54, respectively, comprise plug 14 of FIG. 1. A conductor 90 connects prong 88 to the center arm 92 of switch 26. Arm 92 is shown against switch contact 94. Switch 26 is a single pole double throw switch, and its other contact is shown as 96.

A conductor 98 connects prong 86 to terminal 100 of'bulb 28.

Conductors

90 and 98 comprise cord 12 of FIG. 1. A conductor 102 connects relay contact 80 with switch contact 94. Conductor 104 connects relay contact 78 with switch contact 96. In looking at the circuit of FIG. 2, it is seen that

conductors

90, 102 or 104, 82, and 98 are the means by which power is supplied to bulb 28.

Conductors

60 and 66 are the means by which a control signal is applied to the lamp, i.e., switch 2'4'controls relay 71.

The operation of the circuit may be explained by considering the possible positions of

switches

24 and 26. In the positions shown. the wall switch 24 is closed and energizes the relay 7] placing armature 76 against contact 80. With the center arm of switch 26 against contact 94, a circuit is completed through the source of electrical potential 30 and light bulb '28 via

power conductors

44, 52, 90, 102,82, 98 and 48, thereby energizing bulb 28.

If switch 24 is moved to its open position, the relay 71 willbe de-energized and rest against contact 78. With switch 26 still against contact 94, the chain of conductors whichpreviously completed the circuit is now broken at contact 80 with the result that the light bulb 28 is now in its de-energized or off state.

With switch 24 still in its open position, let it be assumed that switch 26 is moved to its other position with center arm 92 against contact 96. In this case a circuit is completed from source of potential 30 to light bulb 28 via

power conductors

44, 52, 90, 104, 82, 98 and 48. Light bulb 28 is thereby again placed in its energized or lighted condition.

The only remaining combination of switch positions is with center arm 92 against contact 96 and switch 24 closed. In this case, the relay 71 is again energized and armature 76 is brought against contact 80. Now the chain of conductors just recited is broken at contact 78, and light bulb bulb 28. A circuit has been provided which controls the light bulb 28 independently from either the wall switch or the lamp switch. A feature of this arrangement is that failure of the contact asemblies of either the relay or switch 27 does not result in blowing a fuse. Light bulb 28 is always in series with the source ofpotential 30.

FIG. 3 shows a modification of FIG. 1. Like elements in FIGS. 1 and 3 are given like reference numbers. A lamp cord 106 comes from lamp 10 to a plug 108 which is plugged into continuously energized outlet 16. Cord 106, however, contains four conductors; two of the four conductors are power conductors as are and 98 in FIG. 2, and they terminate in prongs which plug into the continuously energized outlet. The other two conductors are control conductors. The control conductors come out of one surface of plug 108 and then continueas a two conductor cord 110, terminating in a plug 112 which plugs into outlet 22 which is controlled by a wall switch. The circuit, of course, operates exactly .as before. This arrangement has the advantages of providing more nearly a single cord and rather easily indentifying the plugs to go to the continuously energized outlet and the switch controlled outlet.

FIGS. 4 and 5 show still another modification of the arrangement of FIG. 1. Here, a four-conductor cord 106 comes from lamp 10 and terminates in special plug 114. As in FIG. 3, the two power conductors terminate in prongs which plug into continuously energized outlet 16. A second set of male prongs is seen protruding, as from the bottom, of plug 114. These prongs arethe terminations of the control conductors. Completion of the control conductor circuit to the switch controlled outlet 22 is made by using a standard extension cord 116. FIG. 5 is an enlarged view of plug 114.

Prongs

118 and 120 are the terminations of the power conductors, and prongs 122 and 124 are the terminations ofthe control conductors.

The advantage of this arrangement is that a lamp with a single cord is provided. lts remote switching capability is employed by means of an extension cord. The lamp may also be used as an ordinary lamp if the extension cord is not used. It should be noted that the exposed prongs are completely insulated from the power circuit and represent no hazard.

FIG. 6 is a circuit diagram for the arrangement of FIG. 4. Again, like elements of the previous drawing are given like reference numbers. FIG. 6 is similar to FIG. 2, but in FIG. 6,

conductors

60, 66, 90 and 98 go into plug 114, which is depicted by phantom line 126.

Conductors

90 and 98 terminate in

prongs

118 and 120, respectively.

Conductors

60 and 66 terminate in

prongs

122 and 124, respectively. Receptacles 128 and 130,

conductors

132 and 134, and prongs 136 and 138 comprise extension cord 116 of FIG. 4.

Conductors

60, 66, 90 and 98 comprise cord 106 of FIG. 4. Operation of the circuit of FIG. 6 is like that of FIG. 2.

FIG. 7 is an adapter which allows a standard lamp to be controlled independently from either a wall switch or an auxiliary switch. A housing 140, containing a relay or some other remotely controlled switch means, is designed to rest on a table near the lamp to be controlled. An auxiliary manual switch control 142 and an electrical outlet 144 are located on the housing. Coming from the housing are

cords

146 and 148 terminating

inplugs

150 and 152, respectively. Cord 146 goes to an outlet controlled by a wall switch and cord 148 goes to a continuously energized outlet. The lamp to be controlled plugs into outlet 144.

FIG. 8 is a wiring diagram of a circuit employable with the arrangement of FIG. 7. Again, elements in FIG. 8 which are like elements in previous Figures are given like reference numbers. It is seen that the circuit of FIG. 8 is much like the circuit of FIG. 2, and its functioning is identical.

Conductors

60 and 66 comprise cord 146, and prongs 56 and 58 comprise plug 150.

Conductors

90 and 98 comprise cord 148, and prongs 86 and 88 comprise plug 152. Auxiliary switch 26 is a manually operable single pole double throw switch.

Receptacles

154 and 156 comprise outlet 144. A lamp l58'generally designated by phantom line 160 has

conductors

162 and 164 terminating in

prongs

166 and 168. These prongs mate with

receptacles

154 and 156, respectively. By going through the switching sequence described for FIG. 2, it will be seen that the light bulb 170 of lamp 158 may be turned on or off independently by either switch 24 or switch 26.

FIG. 9 is another type of adapter for use with a lamp. This adapter has a housing 172 containing a relay or some other remotely controlled switching means. It also carries a set of

male prongs

174 and 176 designed to engage a continuously energized outlet 178. Housing 172 also carries an outlet 180 which receives a plug 182 from the lamp to be controlled. A cord 184 comes from housing 172, which terminates in a plug 186. Plug 186 plugs into a switch controlled outlet 188. A second cord 190 also comes from housing 172, and it goes to a second housing which contains a single pole double throw manually operable auxiliary switch. A switch control knob is shown by 194. Cord 190 is a three wire cord. Case 192 is designed to rest on a table near the lamp to be controlled. The advantage of this arrangement is that there are fewer cords to show on the table.

FIG. is a schematic wiring diagram employable in the arrangement of FIG. 9. Again, like elements are given like reference numbers. Electrically, FIG. 10 is also seen to be identical to FIG. 2. Housing 172 is generally designated by phantom line 196, and the housing is represented as plugging directly into

receptacles

50 and 54 of the continuously energized outlet 178 of FIG. 9 via

prongs

174 and 176. Housing 192 is generally designated by phanton line 198.

Conductors

82, 102 and 104 comprise cord 190.

Conductors

82 and 98 terminate in

receptacles

200 and 202, respectively, and these receptacles comprise outlet 182.

Prongs

166 and 168 from the cord of lamp 158 engage

receptacles

200 and 202. Again, going through the switching sequence described for the circuit of FIG. 2 will show that light bulb 170 may be turned on or off independently from either switch 24 or switch 26.

A simple modification of FIG. 9 would be the removal of cord 184, and the placement of a set of prongs on one face of housing 172. These prongs would then receive an extension cord in a manner similar to that shown in FIG. 4.

FIG. 11 is a solid state circuit which performs the function of the previous relay circuits. A thyristor, in this case a triac, is used to control the power to the bulb. The wall switch and lamp switch combine to control the gate circuit of the thyristor. In FIG. 11, all elements corresponding to like elements in the preceding Figures are given like numbers.

As in the previous circuits, a source of electrical potential supplies a.c. voltage to the circuit. A conductor 204 connects wall switch 24 to a terminal 206 of the primary winding 208 of a transformer 210. Conductor 214 connects terminal 212 of transformer 210 to the ground side of source 30. When the primary winding of transformer 210 is energized, an a.c. voltage appears at

terminals

216 and 218 of secondary winding 220. This voltage is rectified by diode 222 and smoothed by capacitor 224. A resistor 226 is connected in parallel with capacitor 224. Conductor 228 connects to terminal 218, resistor 226, capacitor 224 and the gate terminal 230 of thyristor 232. Diode 222, resistor 226 and capacitor 224 are also connected to a conductor 234. Hence, a source of dc. voltage across capacitor 224 is developed upon closing switch 24. This voltage will have the polarity shown.

Another source of of dc. voltage is developed across capacitor 236 by rectifying the voltage from source 30

terminals

34 and 36 when switch 238 is closed. A conductor 240 is connected to conductor 260 and to one side of switch 238, and a conductor 242 to the other side of switch 238. Conductors 242 connects to resistor 244, which in turn connects to diode 246. Diode 246 connects to conductor 234. A resistor 248 is connected in parallel with capacitor 236. Resistor 248 and capaci tor 236 are connected to conductor 250 and hence, to terminal 34 of source 30. When switch 238 is closed, a dc. voltage with the polarity shown appears across capacitor 236. The components are sized so as to produce equal voltages across

capacitors

224 and 236.

A conductor 250 is connected from source terminal 34 to main terminal-l, 252, of the triac. Main terminal- 2, 254, is connected to conductor 256, which in turn is connected to bulb 258. Bulb 258 is also connected to source terminal 36 by conductor 260.

The operation of the circuit can be understood by going through the possible positions of

switches

24 and 238. With both switches closed, as shown, equal and opposite voltages will appear across

capacitors

224 and 236. In this case, there can be no trigger current. and the triac and bulb will both be off.

If switch 24 is opened, the voltage across 224 due to the rectification by diode 222 will disappear. Now current will flow from the rectifier circuit comprised of diode 246 and capacitor 236 through resistor 226 to gate 230 and main terminal-l, 252. This will turn on the triac and light the lamp.

Leaving switch 24 open and opening switch 258 re.- moves the voltage from both capacitor 224 and capacitor 236. Now there is no gate current and thyristor 232 and bulb are off.

The only remaining condition is with switch 24 closed and 238 open. In this case, voltage appears across 224 due to the rectification by diode 222. Again, current will flow in the gatemain terminal-1 circuit, but now in the opposite direction and through resistor 248. In this condition, the triac will turn on and the light bulb will light.

The circuit of FIG. 11 is shown as a generic circuit and not connected into a specific lamp or adapter arrangement. It is applicable to any of them, however. In using the circuit of FIG. 11, it is obvious that

conductor

204 and 214 would terminate in a plug to go into a switch controlled outlet. Likewise

conductor

250 and 260 would terminate in a plug to go into a continuously energized outlet. Functionally, the transformer could be eliminated. That is, the dc voltage across capacitor 224 could be derived directly from the voltage output of source 30. However, if this were done, plugging either of the necessary plugs into an outlet would result in the prongs of the unconnected plug becoming an exposed source of l 10 V. Use of the isolation transformer prevents this hazard from occurring.

The triac is gated by means of a d.c. current because of the problems associated with more conventional triggering circuits when they may be required to operate from a phase different from that supplying the main terminals of the device. Inpractice, the gate circuit could be connected to either the phase indicated by

terminals

32 and 36 of source 30, or the phase of 34 and 36. Hence, the gate circuit source voltage could be either in phase of 180 out of phase with the source voltage for main terminal-1 and main terminal-2 of triac 222. Most triac triggering circuits are designed to operate from the same phase as the main terminals. The triggering circuit of FIG. Swill operate from any phase relative to the main terminal voltage, since the gate source voltage is used to generate a d.c. voltage.

FIG. 12 is a schematic diagram of another solid state circuit which performs the same function as the previous circuits. Basically, two bipolar thyristors or triacs are used to replace the relay. In FIG. 12, all elements corresponding to like elements in the preceding Figures have been given like numbers.

Conductor 204 is connected to a terminal 206 of the primary winding 208 of a transformer 210. Terminal 212 is connected to conductor 214, which in turn is connected to conductor 260. Terminal 218 of secondary winding 220 is connected to diode 262. Terminal 216 of the secondary winding is connected to terminal 34 of source 30 by

conductors

264 and 266. Diode 262 is connected to a resistor 268 which in turn is connected to the gate terminal 270 of-triac 272. A capacitor 274 is connected to conductor 264 and intermediate resistor 268 and diode 262. Main terminal-l, 276 of triac 272, is connected to conductor 264 by conductor 278. Main terminal-2, 280, is connected to a conductor 282. Triac 284 has gate terminal 286 connected to conductor 282 through resistor 288. Main terminall, 290, of triac 284, is connected to conductor 264. Main terminal-2, 292, is connected to conductor 294.

Conductors

282 and 294 are respectively connected to

contacts

296 and 298 of a single pole double throw switch 300. Switch 300 has a center arm 302 which is connected to conductor 304. Resistor 306 provides a shunt path around switch 300. Light bulb 308 connects to conductor 304 and to ground terminal 36 via conductor 260.

The operation of the circuit of FIG. 12 may be seen I by considering the possible positions of switches-24 and 300. With the switches in the positions shown, the primary winding of transformer 210 is energized and an alternating voltage appears at the secondary winding. This voltage is rectified by diode 262 and smoothed by capacitor 274. Current will flow in the gate-main terminal l circuit of thyristor 272. The gate current is limited by resistor 268.

With switch 24 closed, triac 272 is turned on. When switch 300 is simultaneously-in the positionshown, a conductive path is established through the source 30 and bulb 258 by

conductors

266, 264, 278, 282, 304 and 260. Hence, light bulb 308 is lighted.

Leaving switch 24 closed and changing switch 300 to the position indicated by the dashed line, it is seen the previously recited conductive path is broken at contact 296. Triac 272 is still turned on, and in this condition there is insufficient voltage developed across

main terminals

276 and 280 to permit the turn-on of thyristor 284 via resistor 288. A new conductive path is established through

conductors

266, 264, 278, 282, resistor 306,

conductors

304 and 260. However, the magnitude of the current is limited by resistor 306 to a value which will not brighten the filament of bulb 308.

Leaving switch 300 with arm 302 against contact 298 and opening switch 24, it is seen that triac 272 is now turned-off. In this case, triac 284 is triggered on as soon as the current through bulb 258 and

resistors

306 and 288 reach the gate trigger current. Since the gate trigger current is small, turn-on of 284 will occur within a few degrees of the zero crossing of the source 30 voltage. Hence, a new conductive path is established through

conductors

266, 264, 294, 304 and 260 with the result that the light bulb is lighted.

Leaving switch 24 open and returningswitch 300 to its original position, completes the possible positions of the two switches. In this condition, triac 272 is still off. Triac 284 is still triggered on by the current through resistor 288, but the main terminal-2 path has been interrupted at contact 298. There will still be a conductive path through bulb 258 via

conductors

266, 264, main terminal-1 gate diode of triac 284, resistors 288,

conductors

282, 304 and 260. Again, the magnitude of this current is limited by resistor 288 to a value which will not brighten the filament of bulb 110.

Preferably, resistor 288 is of a non-linear type such as a positive temperature coefficient thermistor. These devices increase their temperature, and hence resistance, with applied voltage. This has the effect of applying a large trigger current to the triac at low voltage, but limits the current at high voltages.

Thus, it is seen that the circuit of FIG. 12 again allows independent control of the light bulb from either the wall switch or the switch associated with the lamp.

Variations of the circuits shown in FIGS. 11 and 12 can be anticipated. For example, integrated circuit zero-crossing switches such as the RCA type CA 305 8' might be used to conserve power in the gate circuit.

When using this type of device, the d.c. circuits shown in FIGS. 11 and 12 would still be used, but their output would be used only to enable or inhibit the zerocrossing switch;

FIG. 13 is a wiring diagram of a'circuit which combines the independent switching functions of the previous circuits with a lamp dimmer circuit. In FIG. 13, the on-off switching function is provided by a circuit like that of FIG. 11, and elements in FIG. 13 like those in FIG. 11 are given like reference numbers.

Triac 232 in FIG. 13, however, does not directly control the lamp current as it does in FIG. 11. The lamp current is controlled by triac 308. Triac 308, inductor 310,

capacitors

312, 314 and

resistors

316 and 318 comprise a phase control circuit for controlling the intensity of lamp 258.

Lamp 258 is connected to source

terminals

34 and 36 via conductor 322, inductor 310, conductor 324, triac 308, and conductors-326, 328 and 250. Conductors 326 and 324 connect to triac 308 at main terminal-l, 330, and main terminal-2, 332, respectively. Diac 320 is connected to the gate terminal 334 of triac 308 as well as to capacitor 314, resistor 318, and triac 232 at main terminal-2 electrode 254.

Inductor 310 and capacitor 312 provide a phase shift in the charging current to capacitor 314,. This charging current flows through fixed resistor 316 and variable resistor 318. When capacitor 314 charges, the voltage builds up across it until the breakdown voltage of the bi-directional diode or diac is reached. When this occurs, capacitor 314 discharges into gate 334 of triac 308 causing it to turn on. The turn-on point in the alternating current cycle at which turn-on occurs is influenced by variable resistor 318. Varying the value of resistor 318 changes the magnitude of the charging current and hence, the time in the cycle at which the voltage across capacitor 314 reaches the breakdown voltage of diac 320.

Now the function of triac 232 in this circuit can be seen. If triac 232 is on, the voltage across capacitor 314 can never reach a value which will break down diac 320 and turn on triac 308. The voltage across capacitor 314 is clamped at the turned on" voltage across triac 232. If triac 232 is off," then the phase control circuit functions in its normal mode. The functioning of the circuit controlling triac 232 in response to the positions of

switches

24 and 238 is exactly the same as that described for FIG. 11.

Thus, it is seen that a circuit has been provided which allows a lamp to be turned on or off independently by either a wall switch or a switch associated with the lamp, while at the same time providing the capability of continuously controlling the intensity of the lamp by means of a variable resistor.

By means of the structures and circuitry disclosed herein, it is seen that improvements have been made over the prior art. A lainp has been provided which may be controlled independently from either a wall switch or the lamp switch. Adapters have been provided which allow a standard lamp to be controlled by a wall switch or an auxiliary switch. The circuitry is such that it will operate regardless of the phasing of the two outlets it is plugged into. Failure of the contacts on either the relay or the auxiliary switch will not result in blowing a fuse because the bulb is always in series with the source of potential. Improved solid state circuitry is provided which functions independently of phasing. Switching circuitry incorporating a lamp dimmer has been provided.

Although only selected and preferred embodiments and modifications of the invention have been disclosed and described, it is apparent that other embodiments and modifications are possible within the scope of the appended claims.

. I claim:

1. A remotely energizable electric lamp assembly for use in combination with a source of electrical potential in circuit with at least first and second duplex-type outlet assemblies spaced from each other, wherein said first duplex-type outlet assembly comprises at least first and second spaced outlets, wherein said second duplextype outlet assembly comprises at least third and fourth spaced outlets, wherein at least said first outlet is in series circuit with a switch member situated electrically between said first outlet and said source, and wherein at least one of said third and fourth outlets is in a continuously closed circuit with said source, said lamp assembly comprising an electric bulb having two effective conditions one of which is an energized state and the other of which is a de-energized state, power conductor means electrically connected to said electrical bulb and adapted for electrical connection to said one of said third and fourth outlets or to said second outlet if only said first outlet of said first outlet assembly is in series circuit with said switch member, said power conductor means including switching means for at times completing an electrical circuit therethrough to said electrical bulb so as to thereby place said electrical bulb in said energized state, control means for at times causing said switching means to complete said electrical circuit through said power conductor means to said bulb and at other times causing said switching means to open said electrical circuit through said power conductor means to thereby place said electrical bulb in said deenergized state, said control means comprising control conductor means adapted for electrical connection to said first outlet of said first outlet assembly or to the other of said third and fourth outlets of said second outlet assembly if only said one of said third and fourth outlets is in a continuously closed circuit with said source, and energizable actuating means being effective whenever an electrical circuit has been completed through said switch member for causing said switching 'means to be switched so as to thereby change the state of said electrical bulb from a then existing one of said two effective conditions to the other of said two effective conditions and manually controlled switch means in circuit with said source and having at least two operating positions, said manually controlled switch means being effective when actuated from one of said at least two operating positions to another of said at least two operating positions to cause the state of said bulb to be changed from an existing one of said two effective conditions to another of said two effective conditions regardless of whether said circuit through said switch member is electrically open or closed, said switch means comprising at least one thyristor, said energizable actuating means comprising gating circuitry, and said manually controlled switch means being in circuit with said source and said gating circuitry.

2. A lamp assembly according to claim 1 wherein said gating circuitry includes an isolation transformer.

3. A remotely energizable electric lamp assembly for use in combination with a source of electrical potential in circuit with at least first and second duplex-type outlet assemblies spaced from each other, wherein said first duplex-type outlet assembly comprises at least first and second spaced outlets, wherein said second duplextype outlet assembly comprises at least third and fourth spaced outlets, wherein at least said first outlet is in series circuit with a switch member situated electrically between said first outlet and said source, and wherein at least one of said third and fourth outlets is in a continuously closed circuit with said source, said lamp assembly comprising an electric bulb having two effective conditions one of which is an energized state and the other of which is a de-energized state, power conductor means electrically connected to said electrical bulb and adapted for electrical connection to said one of said third and fourth outlets or to said second outlet if only said first outlet of said first outlet assembly is in series circuit with said switch member, said power conductor means including switching means for at times completing an electrical circuit therethrough to said electrical bulb so as to thereby place said electrical bulb in said energized state, control means for at times causing said switching means to complete said electrical circuit through said power conductor means to said bulb and at other times causing said switching means to open said electrical circuit through said power conductor means to thereby place said electrical bulb in said deenergized state, said control means comprising control conductor means adapted for electrical connection to said first outlet of said first outlet assembly or to the other of said third and fourth outlets of said second outlet assembly if only said one of said third and fourth outlets is in a continuously closed circuit with said source, and energizable actuating means being effective whenever an electrical circuit has been completed through said switch member for causing said switching means to be switched so as to thereby change the state of said electrical bulb from a then existing one of said two effective conditions to the other of said two effective conditions and manually controlled switch means in circuit with said source and having at least two operating positions, said manually controlled switch means being effective when actuated from one of said at least two operating positions to another of said atleast two operating positions to cause the state of said bulb to be changed from an existing one of said two effective conditions to another of said two effective conditions regardless of whether said circuit through said switch member is electrically open or closed, said power conductor means and said control conductor means being grouped to form a single multiconductor cable coming from said lamp assembly and terminating in a plug having male prongs on one side associated with the said power conductor means and having male prongs on another side associated with said control conductor means.

4. A remotely energizable electric lamp assembly for use in combination with a source of electrical potential in circuit with at least first and second duplex-type outlet assemblies spaced from each other, wherein said first duplex-type outlet assembly comprises at least first and second spaced outlets, wherein said second duplextype outlet assembly comprises at least third and fourth spaced outlets, wherein at least said first outlet is in series circuit with a switch member situated electrically between said first outlet and said source, and wherein at least one of said third and fourth outlets is in a continuously closed circuit with said source, said lamp assembly comprising an electric bulb having two effective conditions one of which is an energized state and the other of which is a de-energized state, power conductor means electrically connected to said electrical bulb and adapted for electrical connection to said one of said third and fourth outlets or to said second outlet if only said first outlet of said first outlet assembly is in series circuit with said switch member, said power conductor means including switching means for at times completing an electrical circuit therethrough to said electrical bulb. so as to thereby place said electrical bulb in said energized state, control means for at times causing said switching means to complete said electrical circuit through said power conductor means to said bulb and at other times causing said switching means to open said electrical circuit through said power conductor means to thereby place said electrical bulb in said deenergized state, said control means comprising control conductor means adapted for electrical connection to said first outlet of said first outlet assembly or to the other of said third and fourth outlets of said second out let assembly if only said one of said third and fourth outlets is in a continuously closed circuit with said source, and energizable actuating means being effective whenever an electrical circuit has been completed through said switch member for causing said switching means to be switched so as to thereby change'the state of said electrical bulb from a then existing one of said two effective conditions to the other of said two effective conditions and manually controlled switch means in circuit with said source and having at least two operating positions, said manually controlled switch means being effective when actuated from one of said at least two operating positions to another of said at least two operating positions to cause the state of said bulb to be changed from an existing one of said two effective conditions to another of said two effective conditions regardless of whether said circuit through said switch member is electrically open or closed, said switching means further comprising a thyristor phase control circuit, and wherein said energizable actuating means acts to enable and inhibit said phase control circuit.

5. An electric switching circuit for energizing an electric lamp having first and second lamp conductors from a source of electric potential having at least two output phases and one of said output phases having a first switch means in circuit therewith, comprising first and second power conductors adapted for connection to any of said output phases and to said first and second lamp conductors, thyristor switching means in series circuit with one of said power conductors, gate control means for said thyristor comprising first and second rectifier circuits in series opposing arrangement and connected to the gate and main terminal-1 electrodes of said thyristor, a first rectifier circuit control means comprising a second switch means connecting said first rectifier circuit and any of said output phases so that said first rectifier circuit is placed in either an energized or de-energized state by said second switch means, a

second rectifier control circuit comprising an isolation transformer having one of its windings connected to said first switch means and having its other winding connected to said second rectifier circuit so that said second rectifier circuit is placed in either an energized or de-energized state by said first switch means, said first switch means and said second switch means being effective to independently energize or de-energize said lamp.

6. An electric switching circuit for energizing an electric lamp having first and second lamp conductors from a source of electric potential having at least two output phases and one of said output phases having a first switch means in circuit therewith; comprising first and second power conductors adapted for connection to any of said output phases and to said first and second lamp conductors, first thyristor switching means in series circuit with one of said power conductors, first gate control means for said first thyristor to provide variable control of the firing angle of said first thyristor, including a bidirectional switching diode and a storage capacitor for providing the energy to turn on said first thyristor, a second thyristor in parallel with said storage capacitor for enabling or inhibiting said first gate control means; a second gate control means for said second thyristor comprising first and second rectifier circuits in series opposing arrangement and connected to the gate and main terminal-l electrodes of said second thyristor, a first rectifier circuit control means comprising a second switch means connecting said first rectifier circuit and any of said output phases so that said first rectifier circuit is placed in either an energized or deenergized state by said second switch means, a second rectifier control circuit comprising an isolation transformer connected to said first switch means and having its other winding connected to said second. rectifier circuit so that said second rectifier circuit is placed in either an energized or de-energized state by said first switch means; said first switch means and said second switch means being effective to independently energize or de-energize said lamp.

7. An adapter assembly for turning an electric lamp assembly on or off independently from either a wall switch controlling a wall outlet or from a manual switch associated with said adapter, said adapter assembly comprising housing means, said housing means having a lower surface for resting on some other surface, manual switch means located for actuation at the upper surface of said housing means, electrical socket means located at a side surface of said housing means for receiving the plug from said electric lamp assembly, power conductor cord means extending from a side surface of said housing means and terminating in an electirc plug for connection to a continuously energized wall outlet, control conductor cord means extending from a side surface of said housing means and terminating in an electric plug for connection to an outlet energized by a wall switch, a switch means within said housing means and in series circuit arrangement with said power conductor cord means and said electrical socket means, and energizable actuating means within said housing means for controlling said switch means and connected to said control conductor means.

8. An adapter assembly according to 7 wherein said switching means and said energizable actuating means comprise a single pole double throw relay and said manual switch means comprises a single pole double throw switch, and said power conductor cord means, said switch means, said manual switch means, and said electrical socket means are in series circuit arrangement.

9. An adapter assembly according to 8 wherein said switch means comprises a thyristor and said energizable actuating means comprises a gating circuit, said gating circuit comprised oftwo series opposing rectifier circuits, one of said rectifier circuits being controlled through the control conductor cord means by a wall switch and the other recitifer circuit being controlled by the manual switch, one of said rectifier circuits having an isolation transformer.

10. An adapter assembly according to 8 wherein said switch means is a phase controlled thyristor circuit, and said energizable actuating means comprises a second thyristor which enables or inhibits said phase controlled thyristorcircuit, the gating circuit for said second thyristor being comprised of two series opposing rectifier circuits, one of said rectifier circuits being controlled through the control conductor cord means by a wall switch and the other rectifier circuit being controlled by the manual switch, one of said rectifier circuits having an isolation transformer.

11. An adapter assembly for turning an electric lamp assembly on or off independently from either a wall switch controlling a wall outlet or from a manual switch associated with said adapter, said adapter assembly comprising a first housing member, said first housing member having a back surface and attached thereto a single pair of male prongs for engagement with a continuously energized wall outlet, said single pair of male prongs being effective to provide electrical power to the assembly and hold the first housing member in position against the wall outlet, an electrical socket means on another surface of said first housing member for receiving the plug from said electric lamp assembly, control conductor cord means extending from a surface of said first housing means and terminating in a plug for electrical connection to a wall outlet controlled by a wall switch, manual switch conductor cord means extending from a face of said first housing member and terminating in a second housing member, said second housing member having a lower surface for resting on some other surface, manual switch means within said second housing member and located for actuation at the upper surface of said second housing member, switch means located within said first housing member and in series circuit arrangement with said male prongs and said electrical socket means, and energizable actuating means within said first housing means for controlling said switch means and connected to said control conductor cord means.

12. An adapter assembly according to 11 wherein said switching means and said energizable actuating means comprise a single pole double throw relay and said manual switch means comprises a single pole double throw switch, and said power conductor cord means, said switch means, said manual switch means, and said electrical socket means are in series circuit ar rangement.

13. An adapter assembly according to 11 wherein said switch means comprises a thyristor and said energizable actuating means comprises a gating circuit, said gating circuit comprised of two series opposing rectifier circuits, .one of said rectifier circuits being controlled through the control conductor cord means by a wall switch and the other rectifier circuit being controlled by the manual switch, one of said rectifier circuits having an isolation transformer.

14. An adapter assembly according to 11 wherein said switch means is a phase controlled thyristor circuit, and said energizable actuating means comprises a second thyristor which enables or inhibits said phase controlled thyristor circuit, the gating circuit for said second thyristor being comprised of two series opposing rectifier circuits, one of said rectifier circuits being controlled through the control conductor cord means by a wall switch and the other rectifier circuit being controlled by the manual switch, one of said rectifier circuits having an isolation transformer.

15. A lamp switching circuit for turning an electric lamp on or off independently from either of two switch stations comprising a source of electrical potential having at least two output phases, power conductor means connected to one of said output phases and said lamp, one of said power conductor means having in series circuit therewith a single pole double throw manual switch and a pair of thyristors having their main terminal 1 electrodes connected together and to said source and their main terminal 2 electrodes connected to the terminals of said manual switch, the armature side of said manual switch being connected to said electric lamp, control conductor means connected to said source through a switch means and to the primary winding of an isolation transformer, the secondary of said isolation transformer being connected to the gate terminal and main terminal 1 of one of said pair of thyristors through a rectifier and filter circuit so as to supply a dc. signal to said one of said pair of thyristors when said switch means completes the circuit between means being effective when turned on and off to alternately turn one or the otherof said pair of thyristors on or off, said circuit being effective to change the state of energization of said lamp when the condition of either the switch means orthe single pole double throw switch is changed.

Claims

1. A remotely energizable electric lamp assembly for use in combination with a source of electrical potential in circuit with at least first and second duplex-type outlet assemblies spaced from each other, wherein said first duplex-type outlet assembly comprises at least first and second spaced outlets, wherein said second duplex-type outlet assembly comprises at least third and fourth spaced outlets, wherein at least said first outlet is in series circuit with a switch member situated electrically between said first outlet and said source, and wherein at least one of said third and fourth outlets is in a continuously closed circuit with said source, said lamp assembly comprising an electric bulb having two effective conditions one of which is an energized state and the other of which is a de-energized state, power conductor means electrically connected to said electrical bulb and adapted for electrical connection to said one of sAid third and fourth outlets or to said second outlet if only said first outlet of said first outlet assembly is in series circuit with said switch member, said power conductor means including switching means for at times completing an electrical circuit therethrough to said electrical bulb so as to thereby place said electrical bulb in said energized state, control means for at times causing said switching means to complete said electrical circuit through said power conductor means to said bulb and at other times causing said switching means to open said electrical circuit through said power conductor means to thereby place said electrical bulb in said de-energized state, said control means comprising control conductor means adapted for electrical connection to said first outlet of said first outlet assembly or to the other of said third and fourth outlets of said second outlet assembly if only said one of said third and fourth outlets is in a continuously closed circuit with said source, and energizable actuating means being effective whenever an electrical circuit has been completed through said switch member for causing said switching means to be switched so as to thereby change the state of said electrical bulb from a then existing one of said two effective conditions to the other of said two effective conditions and manually controlled switch means in circuit with said source and having at least two operating positions, said manually controlled switch means being effective when actuated from one of said at least two operating positions to another of said at least two operating positions to cause the state of said bulb to be changed from an existing one of said two effective conditions to another of said two effective conditions regardless of whether said circuit through said switch member is electrically open or closed, said switch means comprising at least one thyristor, said energizable actuating means comprising gating circuitry, and said manually controlled switch means being in circuit with said source and said gating circuitry.

3. A remotely energizable electric lamp assembly for use in combination with a source of electrical potential in circuit with at least first and second duplex-type outlet assemblies spaced from each other, wherein said first duplex-type outlet assembly comprises at least first and second spaced outlets, wherein said second duplex-type outlet assembly comprises at least third and fourth spaced outlets, wherein at least said first outlet is in series circuit with a switch member situated electrically between said first outlet and said source, and wherein at least one of said third and fourth outlets is in a continuously closed circuit with said source, said lamp assembly comprising an electric bulb having two effective conditions one of which is an energized state and the other of which is a de-energized state, power conductor means electrically connected to said electrical bulb and adapted for electrical connection to said one of said third and fourth outlets or to said second outlet if only said first outlet of said first outlet assembly is in series circuit with said switch member, said power conductor means including switching means for at times completing an electrical circuit therethrough to said electrical bulb so as to thereby place said electrical bulb in said energized state, control means for at times causing said switching means to complete said electrical circuit through said power conductor means to said bulb and at other times causing said switching means to open said electrical circuit through said power conductor means to thereby place said electrical bulb in said de-energized state, said control means comprising control conductor means adapted for electrical connection to said first outlet of said first outlet assembly or to the other of said third and fourth outlets of said second outlet assembly if only said one Of said third and fourth outlets is in a continuously closed circuit with said source, and energizable actuating means being effective whenever an electrical circuit has been completed through said switch member for causing said switching means to be switched so as to thereby change the state of said electrical bulb from a then existing one of said two effective conditions to the other of said two effective conditions and manually controlled switch means in circuit with said source and having at least two operating positions, said manually controlled switch means being effective when actuated from one of said at least two operating positions to another of said at least two operating positions to cause the state of said bulb to be changed from an existing one of said two effective conditions to another of said two effective conditions regardless of whether said circuit through said switch member is electrically open or closed, said power conductor means and said control conductor means being grouped to form a single multiconductor cable coming from said lamp assembly and terminating in a plug having male prongs on one side associated with the said power conductor means and having male prongs on another side associated with said control conductor means.

4. A remotely energizable electric lamp assembly for use in combination with a source of electrical potential in circuit with at least first and second duplex-type outlet assemblies spaced from each other, wherein said first duplex-type outlet assembly comprises at least first and second spaced outlets, wherein said second duplex-type outlet assembly comprises at least third and fourth spaced outlets, wherein at least said first outlet is in series circuit with a switch member situated electrically between said first outlet and said source, and wherein at least one of said third and fourth outlets is in a continuously closed circuit with said source, said lamp assembly comprising an electric bulb having two effective conditions one of which is an energized state and the other of which is a de-energized state, power conductor means electrically connected to said electrical bulb and adapted for electrical connection to said one of said third and fourth outlets or to said second outlet if only said first outlet of said first outlet assembly is in series circuit with said switch member, said power conductor means including switching means for at times completing an electrical circuit therethrough to said electrical bulb so as to thereby place said electrical bulb in said energized state, control means for at times causing said switching means to complete said electrical circuit through said power conductor means to said bulb and at other times causing said switching means to open said electrical circuit through said power conductor means to thereby place said electrical bulb in said de-energized state, said control means comprising control conductor means adapted for electrical connection to said first outlet of said first outlet assembly or to the other of said third and fourth outlets of said second outlet assembly if only said one of said third and fourth outlets is in a continuously closed circuit with said source, and energizable actuating means being effective whenever an electrical circuit has been completed through said switch member for causing said switching means to be switched so as to thereby change the state of said electrical bulb from a then existing one of said two effective conditions to the other of said two effective conditions and manually controlled switch means in circuit with said source and having at least two operating positions, said manually controlled switch means being effective when actuated from one of said at least two operating positions to another of said at least two operating positions to cause the state of said bulb to be changed from an existing one of said two effective conditions to another of said two effective conditions regardless of whether said circuit through said switch member is electricAlly open or closed, said switching means further comprising a thyristor phase control circuit, and wherein said energizable actuating means acts to enable and inhibit said phase control circuit.

5. An electric switching circuit for energizing an electric lamp having first and second lamp conductors from a source of electric potential having at least two output phases and one of said output phases having a first switch means in circuit therewith, comprising first and second power conductors adapted for connection to any of said output phases and to said first and second lamp conductors, thyristor switching means in series circuit with one of said power conductors, gate control means for said thyristor comprising first and second rectifier circuits in series opposing arrangement and connected to the gate and main terminal-1 electrodes of said thyristor, a first rectifier circuit control means comprising a second switch means connecting said first rectifier circuit and any of said output phases so that said first rectifier circuit is placed in either an energized or de-energized state by said second switch means, a second rectifier control circuit comprising an isolation transformer having one of its windings connected to said first switch means and having its other winding connected to said second rectifier circuit so that said second rectifier circuit is placed in either an energized or de-energized state by said first switch means, said first switch means and said second switch means being effective to independently energize or de-energize said lamp.

6. An electric switching circuit for energizing an electric lamp having first and second lamp conductors from a source of electric potential having at least two output phases and one of said output phases having a first switch means in circuit therewith; comprising first and second power conductors adapted for connection to any of said output phases and to said first and second lamp conductors, first thyristor switching means in series circuit with one of said power conductors, first gate control means for said first thyristor to provide variable control of the firing angle of said first thyristor, including a bidirectional switching diode and a storage capacitor for providing the energy to turn on said first thyristor, a second thyristor in parallel with said storage capacitor for enabling or inhibiting said first gate control means; a second gate control means for said second thyristor comprising first and second rectifier circuits in series opposing arrangement and connected to the gate and main terminal-1 electrodes of said second thyristor, a first rectifier circuit control means comprising a second switch means connecting said first rectifier circuit and any of said output phases so that said first rectifier circuit is placed in either an energized or de-energized state by said second switch means, a second rectifier control circuit comprising an isolation transformer connected to said first switch means and having its other winding connected to said second rectifier circuit so that said second rectifier circuit is placed in either an energized or de-energized state by said first switch means; said first switch means and said second switch means being effective to independently energize or de-energize said lamp.

9. An adapter assembly according to 8 wherein said switch means comprises a thyristor and said energizable actuating means comprises a gating circuit, said gating circuit comprised of two series opposing rectifier circuits, one of said rectifier circuits being controlled through the control conductor cord means by a wall switch and the other recitifer circuit being controlled by the manual switch, one of said rectifier circuits having an isolation transformer.

10. An adapter assembly according to 8 wherein said switch means is a phase controlled thyristor circuit, and said energizable actuating means comprises a second thyristor which enables or inhibits said phase controlled thyristor circuit, the gating circuit for said second thyristor being comprised of two series opposing rectifier circuits, one of said rectifier circuits being controlled through the control conductor cord means by a wall switch and the other rectifier circuit being controlled by the manual switch, one of said rectifier circuits having an isolation transformer.

12. An adapter assembly according to 11 wherein said switching means and said energizable actuating means comprise a single pole double throw relay and said manual switch means comprises a single pole double throw switch, and said power conductor cord means, said switch means, said manual switch means, and said electrical socket means are in series circuit arrangement.

13. An adapter assembly according to 11 wherein said switch means comprises a thyristor and said energizable actuating means comprises a gating circuit, said gating circuit comprised of two series opposing rectifier circuits, one of said rectifier circuits being controlled through the control conductor cord means by a wall switch and the other rectifier circuit being controlled by the manual switch, one of said rectifier circuits having an isolation transformer.

15. A lamp switching circuit for turning an electric lamp on or off independently from either of two switch stations comprising a source of electrical potential having at least two output phases, power conductor means connected to one of said output phases and said lamp, one of said power conductor means having in series circuit therewith a single pole double throw manual switch and a pair of thyristors having their main terminal 1 electrodes connected together and to said source and their main terminal 2 electrodes connected to the terminals of said manual switch, the armature side of said manual switch being connected to said electric lamp, control conductor means connected to said source through a switch means and to the primary winding of an isolation transformer, the secondary of said isolation transformer being connected to the gate terminal and main terminal 1 of one of said pair of thyristors through a rectifier and filter circuit so as to supply a d.c. signal to said one of said pair of thyristors when said switch means completes the circuit between said source and said primary winding, resistor means connected intermediate the main terminal 2 electrode of said one of said pair of thyristors and the gate terminal of the other of said pair of thyristors, resistor means connected intermediate the main terminal 2 electrode of said one of said pair of thyristors and the armature of said single pole double throw switch, said switch means being effective when turned on and off to alternately turn one or the other of said pair of thyristors on or off, said circuit being effective to change the state of energization of said lamp when the condition of either the switch means or the single pole double throw switch is changed.