CA1264351A - Controlling lighting elements in response to ambient light intensity - Google Patents
Controlling lighting elements in response to ambient light intensityInfo
- Publication number
- CA1264351A CA1264351A CA000494806A CA494806A CA1264351A CA 1264351 A CA1264351 A CA 1264351A CA 000494806 A CA000494806 A CA 000494806A CA 494806 A CA494806 A CA 494806A CA 1264351 A CA1264351 A CA 1264351A
- Authority
- CA
- Canada
- Prior art keywords
- voltage
- triac
- terminal
- ambient light
- circumferentially
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
- H05B47/10—Controlling the light source
- H05B47/105—Controlling the light source in response to determined parameters
- H05B47/11—Controlling the light source in response to determined parameters by determining the brightness or colour temperature of ambient light
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
Landscapes
- Circuit Arrangement For Electric Light Sources In General (AREA)
Abstract
INVENTION: CONTROLLING LIGHTING ELEMENTS IN
RESPONSE TO AMBIENT LIGHT INTENSITY
INVENTOR: KOSTA PELONIS
ABSTRACT OF THE DISCLOSURE
A two-terminal device is described which can be series connected with an incandescent or fluorescent lighting element to turn the lighting element on and off in response to ambient light intensity. The device includes a triac which conducts current through the lighting element, a diac connected to the trigger terminal of the triac to set a turn-on voltage threshold, and a capacitive voltage divider whose divider node is connected to the diac and which normally generates from the voltage across the triac a triggering signal that initiates triac conduction. A photoresistive element shunts one of the divider capacitors and suppresses triac triggering when ambient light intensity exceed a predetermined level. A neon light adjacent the photoresistive element and powered by the voltage difference across the triac prevents off-on oscillation in response to light received from the lighting element itself.
RESPONSE TO AMBIENT LIGHT INTENSITY
INVENTOR: KOSTA PELONIS
ABSTRACT OF THE DISCLOSURE
A two-terminal device is described which can be series connected with an incandescent or fluorescent lighting element to turn the lighting element on and off in response to ambient light intensity. The device includes a triac which conducts current through the lighting element, a diac connected to the trigger terminal of the triac to set a turn-on voltage threshold, and a capacitive voltage divider whose divider node is connected to the diac and which normally generates from the voltage across the triac a triggering signal that initiates triac conduction. A photoresistive element shunts one of the divider capacitors and suppresses triac triggering when ambient light intensity exceed a predetermined level. A neon light adjacent the photoresistive element and powered by the voltage difference across the triac prevents off-on oscillation in response to light received from the lighting element itself.
Description
1;~64351 FIELD OF T~E INVENT~ON
The invention relates generally to lighting control, and more particularly, to the automatic actuation of incandescent and fluorescent lighting elements in response to ambient light intensity.
S BACKGROUND OF THE TNVENTION
Increasing energy costs have created a demand for devices which automatically turn lighting off during the day when natural light is avai1able and turn lighting on at night. For example, it is now common to actuate lights external to a building with circuitry employing a photodetecting element responsive to ambientlight. The photodetecting device is normally mounted behind the associated lighting element where light from the lighting element will not affect detection. Basically, on-off oscillation is avoided by shielding the photodetective element from the lighting element which it controls.
There is also a need for automatic lighting control indoors. Such lighting control would not only permit energy conservation, but also theft prevention, being used to create the impression of occupancy. At present, automatic timers are the principal mechanism for regulating lighting in the interior of a house or building.
Photodetecting devices would provide an alternative, and in many instances much less expensive, means of automatically controlling indoor lighting. However, conventional photodetecting devices used in outdoor lighting control are more difficult to shield in indoor applications, and are too readily subject to on-off oscillation.
It is accordingly one object of the invention to provide a device which regulates the operation of a lighting element in response to ambient light intensity and which can be operated in the presence of light generated by the lighting element itself.
It is a further object of the invention in various embodiments to provide devices of the above nature which can automatically control either incandescent or fluorescent lighting elements, and which can be manufactured essentially as ~6435~
two-terminal devices that may be conveniently series connected with the controlled lighting element.
BRTEF SUMMA~Y OF THE I VENTI~N
In one aspect, the invention provides a device for controlling operation 5 of electrically powered lighting element in response to ambient light intensity, which includes switching means adapted to conduct light through the lighting element and requiring periodic triggering to remain in a conductive state. Light sensing means are provided to sense and indicate ambient light intensity, and also triggering means for periodically triggering the switching means whenever the indicated ambient light 10 intensity drops below a threshold level. Light generating means (not intended for general illurnination of the environment) are positioned proximate to the light sensing means, and generate light of a predetermined intensity thereby augmenting the indicated ambient light intensity. The light generating means are actuated in response to the conduction state of the switching means, the light generating means generating 15 light whenever the switching means are in a non-conductive state (the controlled lighting element being off), and are otherwise inoperative (the controlled lighting element being on).
Accordingly, the device is capable of automatically regulating operation of an electrically powered lighting element even in the presence of the light generated 20 by the lighting element. The light generating means effectively shift the light intensity threshold level required to trigger conduction through the switching means whenever the lighting element is powered. Alternatively, the light generating means may be viewed as augmenting indicated ambient light intensity, whenever the lighting element is inoperative, to make the device effectively responsive only to components of 25 ambient light intensity other than those contributed by the lighting element.
DESCRIE~ON OF THE DRAWIN~;S
The invention will be better understood with reference to drawings 126435i illustrating preferred embodiments in which:
fig. 1 is a basic two-terrninal device for controlling electrically powered lighting elements in response to ambient light intensity;
fig. 2 is a perspective view of a second device specifically adapted for 5 control of incandescent lighting; and, fig. 3 is a schematic representation of electronic circuitry associated with the device of fig. 2.
pESCRlPT~ON OF PREFERRED EMBODIMENTS
Reference is made to fig. 1 which illustrates a two-terminal device 20 10 series connected to a lighting element 22 that is powered by a 120 volt AC line source at a pair of line terrninals 24. The lighting element 22 may be of either the incandescent or fluorescent variety. The general function of the device 20 is to activate the lighting element 22 when, for exarnple, a room in which the lighting element 22 is located becomes dark, and to shut off the lighting element 22 when light in the room 15 from outdoors is otherwise adequate for the intended use of the room. This function is performed while a light sensor associated with the device 20 is fully exposed to the light generated by the lighting element 22.
The device 20 includes a bidirectional switching element, a conventional triac 26. Conduction in the triac 26 is initiated by the voltage difference between the 20 device terminals 28, 30 and receipt of a trigger signal at its tngger terminal 32. When triggered for conduction, the triac 26 couples the device terminals 28,30 thereby permitting conduction of current through the lighting element 22. Triac conduction is self-extinguishing (the triac 26 assuming a non-conductive state whenever current through the triac 26 drops to 0 and the voltage across the triac drops to 0), and 25 accordingly the triac 26 requires triggering in each half-cycle of the AC line voltage to remain in a substantially continuous conductive state.
The triac triggering signal is generated from the voltage difference ~?
~26~:~5~
s between the device terminals 28,30 (or alternatively viewed, from the voltage across the triac 26) by a capacitive voltage divider 34. The divider 34 includes a capacitor 36 series connected to a capacitor 38 at a divider node 40. The divider node 40 is coupled to the triac trigger terminal 32 by a bidirectional serniconductor device, a diac 42, which has a turn-on voltage of about 8 volts. Accordingly, the voltage divider 34 tends to trigger the triac 26 in each half-cycle of the AC line voltage when the voltage difference between the device terminals 28, 30 rises to about 18 volts. A resistor 44 in series with the capacitor 36 serves to lirnit surge currents through the capacitive Yoltage divider 34 which are apt to occur with each reversal of the polarity of the AC line voltage, and does not substantially affect the preselected divider ratio.
Ambient light is sensed by a photoresistor 46. The resistance of the photoresistor 46 decreases with increasing intensity of light incident upon the photoresistor 46, and consequently indicates ambient light intensity. The photoresistor 46 couples the divider node 40 to the device terminal 30, shunting the divider capacitor 38. When ambient lighting intensity is sufficiently great, the photoresistor 46 has a small impedence, and effectively shorts the capacitor 38. The voltage differencebetween the divider node 40 and the device terminal 30 is consequently reduced throughout each half-cycle of the AC line voltage to less than 8 volts, preventing triggering of the triac 26 and illumination of the lighting element 22. However, when ambient light intensity drops below a certain level, the resistance of the photoresistor 46 increases and the photoresistor 46 no longer significantly affects the operation of the voltage divider 34. The triac 26 is then periodically triggered for conduction, and the lighting element 22 illuminated.
A neon light 48 with a 68 volt turn-on threshold is positioned physically ~i 25 proximate to the photoresistor 46, and is actuated in a manner that prevents on-off oscillation of the lighting element 22. The neon light 48 is connected in parallel with ~' the triac 26, and accordingly, is powered by the voltage difference across the triac 26 , ~ .
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(alternatively viewed as the voltage difference between the device terminals 28,30) and actuated in response to the conduction state of the triac 26. When the triac 26 is in a non-conductive state (the lighting element 22 being off) substantially all the AC line voltage appears across the device terminals 28,30, and accordingly in each half-cycle S of the AC line voltage the neon light 48 is actuated to generate light. When the triac 26 is in a conductive state, however, the voltage difference between the device terminals 28,30 does not exceed 2 volts, and accordingly the neon light 48 is inoperative. A
resistor 50 ensures that excessive current flow through the neon light 48 does not occur.
The neon light 48 when actuated effectively augments the ambient light intensity indicated by the photoresistor 46. The indicated ambient light intensity is increased a predetermined amount, dependant principally on the relative spacing of the photoresistor 46 and neon light 48 and on the power rating of the neon light 48. In any given application the amount by which the indicated ambient light intensity is 15 augmented should correspond to and exceed the expected component of ambient light intensity, at the photoresistor 46, attributable to the lighting element 22. The neon light 48 can alternatively be viewed as effectively creating a hysteresis in the turn-off ambient light threshold level. That threshold level is automatically increased whenever the triac 26 is in a conductive state (the lighting element 22 being illuminated) thereby 20 making the device 20 non-responsive to the operating state of the lighting element 22.
A significant advantage of this type of operation is that both incandescent and fluorescent lighting can be accommodated. With fluorescent lighting the inductive load presented by associated ballasts tends to phase shift voltage and current between the device terrninals 28,30, an the current conducted through the 25 device 20 can significantly lag the voltage appearing between the device terminals 28, 30. Thus, when an inductive load such as a fluorescent luminaire is turned on, the device will tend to remain on even though the light contribution of the luminaire will lZ64351 decrease the resistance of the photosensor 46. The provision of the light 48 operating as described overcomes this problem, ensuring turn off. A small inductor 52 is series connected with the triac 26 between the device terminals 28, 30 to prevent sudden current changes in the case of resistive loading. The inductor 52 may be eliminated S from a device which is intended solely for use with inductive lighting elements. The capacitor 36 and resistor 44 act as a snubber limiting rapid voltage changes in the case of inductive loads.
Figs. 2 and 3 illustrate an alternative a device 60 adapted specifically for control of incandescent lighting elements in response to ambient light, but providing a number of additional control functions. The device 60 is effectively a modification of the device 20 to permit those additional functions which include dimming, variation of the threshold ambient light intensity for turn-on, by-passing of control in response to ambient light intensity, and total switching off of control circuitry and the associated lighting element. Since the device 60 is in effect an embellishment of the device 20, 1~ incorporating all components to be found in the device 20, like components have been labelled with like reference numerals, and general operation will not be described in detail.
A general external view of the device 60 is provided in fig. 2. The device includes a conventional metal housing 62 which can be mounted in a wall in a manner conventional to most light switches. Two leads 64, 65 extend from the housing 62 to permit series connection of the device 60 with a lighting element to be controlled. The device 60 has a plastic decorative panel 64 which during installation of the device is mounted flush against a wall (once again in a conventional manner). On the surface of the panel 64 are located a number of circuit components of the device 60, including a rotary switch 66 with five settings or positions, the photoresistor 46 described above, and close thereto the neon light 48. Operation of the device 60 will be described with reference to the schematic diagram of fig. 2 representing various lZ~;A~S~
circuit components to be found within the housing 62.
The rotary switch 66 has ten poles indicated by the reference numerals 1-10 inclusive which are equally spaced-apart circumferentially in a circular arrangement. A wiper 68 is rotatably mounted within the switch 66, and has a pair of 5 diametrically opposing, electrically insulated wiper end portions 70, 72. One wiper end portion electrically connects one adjacent pair of poles, whenever the other wiper end portion electrically connects another adjacent pair of poles, positioned diametrically opposite the first pair. For example, as illustrated, the wiper end portion 70 electrically connects the poles 1, 2 while the wiper 72 electrically connects10 diametrically opposite poles 6, 7. The construction of the rotary switch 66 is conventional.
The electrical coupling of the various poles of the rotary switch 66 is significant, and provides a very inexpensive means for conveniently implementing the various functions intended of the device 60. In describing the electrical connection 15 existing between the various switch poles, both in this disclosure and the appended claims, one pole (namely pole 1) is arbitrarily designated a circumferentially first pole, and the positions of the other poles are specified according to circumferential position relative to the first pole . Clockwise or counterclockwise orientation of the poles relative to the arbitrary first pole is inconsequential to proper electrical connection of 20 the rotary switch 66, so long as the pole positions are consistently designated in either a clockwise or counterclockwise direction.
Circumferentially first and fifth switch poles 1, 5 are connected by a diode 74. The fifth pole 5 is also electrically coupled (through the inductor 52) to the device terrninal 28. These connections are in furtherance of an arrangement which 25 perrnits dimrning or effective by-passing of the device 60 for regular lighting control.
Circumferentially second and third poles 2, 3 are coupled by a resistor 76, which is also series connected with the photoresistor 46 and couples the photoresistor 46 to the '~-/
.'.:, . . .
~Z643Sl device terminal 30. pole 3 is connected to the device terminal 30, and pole 2 isconnected to the circumferentially seventh pole 6. Circumferentially fouIth, eighth, ninth and tenth poles 4,8, 9, 10 are electrically connected together and to an output terminal 78 (which in tum is connected to one of the leads 64, 65).
S The wiper 68, as illustrated, couples poles 1 and 2, and diametrically opposing poles 6 and 6. Accordingly, output terminal 78 is isolated from device terminal 28, and the lighting system including the lighting element 22 is in an off state.
The wiper 68 can be rotated clockwise to a next position in which poles
The invention relates generally to lighting control, and more particularly, to the automatic actuation of incandescent and fluorescent lighting elements in response to ambient light intensity.
S BACKGROUND OF THE TNVENTION
Increasing energy costs have created a demand for devices which automatically turn lighting off during the day when natural light is avai1able and turn lighting on at night. For example, it is now common to actuate lights external to a building with circuitry employing a photodetecting element responsive to ambientlight. The photodetecting device is normally mounted behind the associated lighting element where light from the lighting element will not affect detection. Basically, on-off oscillation is avoided by shielding the photodetective element from the lighting element which it controls.
There is also a need for automatic lighting control indoors. Such lighting control would not only permit energy conservation, but also theft prevention, being used to create the impression of occupancy. At present, automatic timers are the principal mechanism for regulating lighting in the interior of a house or building.
Photodetecting devices would provide an alternative, and in many instances much less expensive, means of automatically controlling indoor lighting. However, conventional photodetecting devices used in outdoor lighting control are more difficult to shield in indoor applications, and are too readily subject to on-off oscillation.
It is accordingly one object of the invention to provide a device which regulates the operation of a lighting element in response to ambient light intensity and which can be operated in the presence of light generated by the lighting element itself.
It is a further object of the invention in various embodiments to provide devices of the above nature which can automatically control either incandescent or fluorescent lighting elements, and which can be manufactured essentially as ~6435~
two-terminal devices that may be conveniently series connected with the controlled lighting element.
BRTEF SUMMA~Y OF THE I VENTI~N
In one aspect, the invention provides a device for controlling operation 5 of electrically powered lighting element in response to ambient light intensity, which includes switching means adapted to conduct light through the lighting element and requiring periodic triggering to remain in a conductive state. Light sensing means are provided to sense and indicate ambient light intensity, and also triggering means for periodically triggering the switching means whenever the indicated ambient light 10 intensity drops below a threshold level. Light generating means (not intended for general illurnination of the environment) are positioned proximate to the light sensing means, and generate light of a predetermined intensity thereby augmenting the indicated ambient light intensity. The light generating means are actuated in response to the conduction state of the switching means, the light generating means generating 15 light whenever the switching means are in a non-conductive state (the controlled lighting element being off), and are otherwise inoperative (the controlled lighting element being on).
Accordingly, the device is capable of automatically regulating operation of an electrically powered lighting element even in the presence of the light generated 20 by the lighting element. The light generating means effectively shift the light intensity threshold level required to trigger conduction through the switching means whenever the lighting element is powered. Alternatively, the light generating means may be viewed as augmenting indicated ambient light intensity, whenever the lighting element is inoperative, to make the device effectively responsive only to components of 25 ambient light intensity other than those contributed by the lighting element.
DESCRIE~ON OF THE DRAWIN~;S
The invention will be better understood with reference to drawings 126435i illustrating preferred embodiments in which:
fig. 1 is a basic two-terrninal device for controlling electrically powered lighting elements in response to ambient light intensity;
fig. 2 is a perspective view of a second device specifically adapted for 5 control of incandescent lighting; and, fig. 3 is a schematic representation of electronic circuitry associated with the device of fig. 2.
pESCRlPT~ON OF PREFERRED EMBODIMENTS
Reference is made to fig. 1 which illustrates a two-terminal device 20 10 series connected to a lighting element 22 that is powered by a 120 volt AC line source at a pair of line terrninals 24. The lighting element 22 may be of either the incandescent or fluorescent variety. The general function of the device 20 is to activate the lighting element 22 when, for exarnple, a room in which the lighting element 22 is located becomes dark, and to shut off the lighting element 22 when light in the room 15 from outdoors is otherwise adequate for the intended use of the room. This function is performed while a light sensor associated with the device 20 is fully exposed to the light generated by the lighting element 22.
The device 20 includes a bidirectional switching element, a conventional triac 26. Conduction in the triac 26 is initiated by the voltage difference between the 20 device terminals 28, 30 and receipt of a trigger signal at its tngger terminal 32. When triggered for conduction, the triac 26 couples the device terminals 28,30 thereby permitting conduction of current through the lighting element 22. Triac conduction is self-extinguishing (the triac 26 assuming a non-conductive state whenever current through the triac 26 drops to 0 and the voltage across the triac drops to 0), and 25 accordingly the triac 26 requires triggering in each half-cycle of the AC line voltage to remain in a substantially continuous conductive state.
The triac triggering signal is generated from the voltage difference ~?
~26~:~5~
s between the device terminals 28,30 (or alternatively viewed, from the voltage across the triac 26) by a capacitive voltage divider 34. The divider 34 includes a capacitor 36 series connected to a capacitor 38 at a divider node 40. The divider node 40 is coupled to the triac trigger terminal 32 by a bidirectional serniconductor device, a diac 42, which has a turn-on voltage of about 8 volts. Accordingly, the voltage divider 34 tends to trigger the triac 26 in each half-cycle of the AC line voltage when the voltage difference between the device terminals 28, 30 rises to about 18 volts. A resistor 44 in series with the capacitor 36 serves to lirnit surge currents through the capacitive Yoltage divider 34 which are apt to occur with each reversal of the polarity of the AC line voltage, and does not substantially affect the preselected divider ratio.
Ambient light is sensed by a photoresistor 46. The resistance of the photoresistor 46 decreases with increasing intensity of light incident upon the photoresistor 46, and consequently indicates ambient light intensity. The photoresistor 46 couples the divider node 40 to the device terminal 30, shunting the divider capacitor 38. When ambient lighting intensity is sufficiently great, the photoresistor 46 has a small impedence, and effectively shorts the capacitor 38. The voltage differencebetween the divider node 40 and the device terminal 30 is consequently reduced throughout each half-cycle of the AC line voltage to less than 8 volts, preventing triggering of the triac 26 and illumination of the lighting element 22. However, when ambient light intensity drops below a certain level, the resistance of the photoresistor 46 increases and the photoresistor 46 no longer significantly affects the operation of the voltage divider 34. The triac 26 is then periodically triggered for conduction, and the lighting element 22 illuminated.
A neon light 48 with a 68 volt turn-on threshold is positioned physically ~i 25 proximate to the photoresistor 46, and is actuated in a manner that prevents on-off oscillation of the lighting element 22. The neon light 48 is connected in parallel with ~' the triac 26, and accordingly, is powered by the voltage difference across the triac 26 , ~ .
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(alternatively viewed as the voltage difference between the device terminals 28,30) and actuated in response to the conduction state of the triac 26. When the triac 26 is in a non-conductive state (the lighting element 22 being off) substantially all the AC line voltage appears across the device terminals 28,30, and accordingly in each half-cycle S of the AC line voltage the neon light 48 is actuated to generate light. When the triac 26 is in a conductive state, however, the voltage difference between the device terminals 28,30 does not exceed 2 volts, and accordingly the neon light 48 is inoperative. A
resistor 50 ensures that excessive current flow through the neon light 48 does not occur.
The neon light 48 when actuated effectively augments the ambient light intensity indicated by the photoresistor 46. The indicated ambient light intensity is increased a predetermined amount, dependant principally on the relative spacing of the photoresistor 46 and neon light 48 and on the power rating of the neon light 48. In any given application the amount by which the indicated ambient light intensity is 15 augmented should correspond to and exceed the expected component of ambient light intensity, at the photoresistor 46, attributable to the lighting element 22. The neon light 48 can alternatively be viewed as effectively creating a hysteresis in the turn-off ambient light threshold level. That threshold level is automatically increased whenever the triac 26 is in a conductive state (the lighting element 22 being illuminated) thereby 20 making the device 20 non-responsive to the operating state of the lighting element 22.
A significant advantage of this type of operation is that both incandescent and fluorescent lighting can be accommodated. With fluorescent lighting the inductive load presented by associated ballasts tends to phase shift voltage and current between the device terrninals 28,30, an the current conducted through the 25 device 20 can significantly lag the voltage appearing between the device terminals 28, 30. Thus, when an inductive load such as a fluorescent luminaire is turned on, the device will tend to remain on even though the light contribution of the luminaire will lZ64351 decrease the resistance of the photosensor 46. The provision of the light 48 operating as described overcomes this problem, ensuring turn off. A small inductor 52 is series connected with the triac 26 between the device terminals 28, 30 to prevent sudden current changes in the case of resistive loading. The inductor 52 may be eliminated S from a device which is intended solely for use with inductive lighting elements. The capacitor 36 and resistor 44 act as a snubber limiting rapid voltage changes in the case of inductive loads.
Figs. 2 and 3 illustrate an alternative a device 60 adapted specifically for control of incandescent lighting elements in response to ambient light, but providing a number of additional control functions. The device 60 is effectively a modification of the device 20 to permit those additional functions which include dimming, variation of the threshold ambient light intensity for turn-on, by-passing of control in response to ambient light intensity, and total switching off of control circuitry and the associated lighting element. Since the device 60 is in effect an embellishment of the device 20, 1~ incorporating all components to be found in the device 20, like components have been labelled with like reference numerals, and general operation will not be described in detail.
A general external view of the device 60 is provided in fig. 2. The device includes a conventional metal housing 62 which can be mounted in a wall in a manner conventional to most light switches. Two leads 64, 65 extend from the housing 62 to permit series connection of the device 60 with a lighting element to be controlled. The device 60 has a plastic decorative panel 64 which during installation of the device is mounted flush against a wall (once again in a conventional manner). On the surface of the panel 64 are located a number of circuit components of the device 60, including a rotary switch 66 with five settings or positions, the photoresistor 46 described above, and close thereto the neon light 48. Operation of the device 60 will be described with reference to the schematic diagram of fig. 2 representing various lZ~;A~S~
circuit components to be found within the housing 62.
The rotary switch 66 has ten poles indicated by the reference numerals 1-10 inclusive which are equally spaced-apart circumferentially in a circular arrangement. A wiper 68 is rotatably mounted within the switch 66, and has a pair of 5 diametrically opposing, electrically insulated wiper end portions 70, 72. One wiper end portion electrically connects one adjacent pair of poles, whenever the other wiper end portion electrically connects another adjacent pair of poles, positioned diametrically opposite the first pair. For example, as illustrated, the wiper end portion 70 electrically connects the poles 1, 2 while the wiper 72 electrically connects10 diametrically opposite poles 6, 7. The construction of the rotary switch 66 is conventional.
The electrical coupling of the various poles of the rotary switch 66 is significant, and provides a very inexpensive means for conveniently implementing the various functions intended of the device 60. In describing the electrical connection 15 existing between the various switch poles, both in this disclosure and the appended claims, one pole (namely pole 1) is arbitrarily designated a circumferentially first pole, and the positions of the other poles are specified according to circumferential position relative to the first pole . Clockwise or counterclockwise orientation of the poles relative to the arbitrary first pole is inconsequential to proper electrical connection of 20 the rotary switch 66, so long as the pole positions are consistently designated in either a clockwise or counterclockwise direction.
Circumferentially first and fifth switch poles 1, 5 are connected by a diode 74. The fifth pole 5 is also electrically coupled (through the inductor 52) to the device terrninal 28. These connections are in furtherance of an arrangement which 25 perrnits dimrning or effective by-passing of the device 60 for regular lighting control.
Circumferentially second and third poles 2, 3 are coupled by a resistor 76, which is also series connected with the photoresistor 46 and couples the photoresistor 46 to the '~-/
.'.:, . . .
~Z643Sl device terminal 30. pole 3 is connected to the device terminal 30, and pole 2 isconnected to the circumferentially seventh pole 6. Circumferentially fouIth, eighth, ninth and tenth poles 4,8, 9, 10 are electrically connected together and to an output terminal 78 (which in tum is connected to one of the leads 64, 65).
S The wiper 68, as illustrated, couples poles 1 and 2, and diametrically opposing poles 6 and 6. Accordingly, output terminal 78 is isolated from device terminal 28, and the lighting system including the lighting element 22 is in an off state.
The wiper 68 can be rotated clockwise to a next position in which poles
2 and 3 are electrically connected and also the diametrically opposing poles 7 and 8. In this switch state, the resistor 76 is effectively short-circuited, the terminals 28,78 electrically coupled through the triac 26, and actuation of the lighting element 22 is then responsive to ambient light intensity, exactly as descAbed with reference to the device 20. Movement of the wiper 68 clockwise to a next position in which poles 3 and 4 are connected, and diametrically opposing poles 8 and 9, connected, effectively results in a shifting of the ambient light turn-on threshold. The resistor 76 is now series connected to the photoresistor 46, and accordingly, the triac 26 will be triggered for conduction only in response to relatively higher ambient light intensity.
Accordingly, the sensitivity of the photodetection can be selectively increased or decreased.
Movement of the wiper 68 clockwise to the next position, electrically couples poles 4 and 5 and diametrically opposing poles 9 and 10, causes a by-passing of the triac 26 and associated photodetection and triggering circuitry. In this wiper orientation, the lighting element 22 is simply turned on, and operation is not responsive to ambient light levels.
Rotation of the wiper 68 clockwise to the next position coupling poles 1 anfl 10 and diametrically opposing poles 5 and 6. This switch state also results in bypassing of the triac 26 and associated photodetection and trigger circuitry, but also ~64351 engages operation of the diode 74. In this wiper position, current through the lighting element 22 is conducted through the diode 74 which accordingly reduces power consumption in half, and the light element 22 is accordingly dimmed. It will be appreciated that any two-terminal diode-type device can be substituted for the diode 5 74, and the only requirement is that the device have low power consumption andselectively pass current in response to voltages across the device.
The device 60 will accordingly be seen to provide a myriad of functions beyond those of the device 20 without complex circuitry and costly components. In particular, the light 22 can be switched off, turned on, dimmed, and made responsive 10 to ambient light intensity at two different threshold levels.
It will be appreciated that particular embodiments of the invention have been described, and that modi~lcations may be made therein without departing from the spirit of the invention or the scope of the appended claims.
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Accordingly, the sensitivity of the photodetection can be selectively increased or decreased.
Movement of the wiper 68 clockwise to the next position, electrically couples poles 4 and 5 and diametrically opposing poles 9 and 10, causes a by-passing of the triac 26 and associated photodetection and triggering circuitry. In this wiper orientation, the lighting element 22 is simply turned on, and operation is not responsive to ambient light levels.
Rotation of the wiper 68 clockwise to the next position coupling poles 1 anfl 10 and diametrically opposing poles 5 and 6. This switch state also results in bypassing of the triac 26 and associated photodetection and trigger circuitry, but also ~64351 engages operation of the diode 74. In this wiper position, current through the lighting element 22 is conducted through the diode 74 which accordingly reduces power consumption in half, and the light element 22 is accordingly dimmed. It will be appreciated that any two-terminal diode-type device can be substituted for the diode 5 74, and the only requirement is that the device have low power consumption andselectively pass current in response to voltages across the device.
The device 60 will accordingly be seen to provide a myriad of functions beyond those of the device 20 without complex circuitry and costly components. In particular, the light 22 can be switched off, turned on, dimmed, and made responsive 10 to ambient light intensity at two different threshold levels.
It will be appreciated that particular embodiments of the invention have been described, and that modi~lcations may be made therein without departing from the spirit of the invention or the scope of the appended claims.
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Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A two-terminal device adapted to be series connected with an electric lighting element powered by an AC voltage to control operation of the lighting element in response to ambient light intensity, comprising:
bidirectional switching means for electrically coupling the two device terminals for conduction of current, the bidirectional switching means being actuated for conduction by the voltage difference between the two device terminals and requiring triggering in each half-cycle of the AC voltage to remain in a conductive state;
a photoresistive element whose resistance varies with the intensity of light incident on the element thereby sensing and indicating ambient light intensity;
triggering means powered by the voltage difference between the two device terminals and responsive to the resistance of the photoresistive element for triggering the bidirectional switching means in each half-cycle of the AC voltage when the indicated ambient light intensity drops below a threshold level; and, light generating means positioned proximate to the light sensing means for generating light of predetermined intensity when actuated thereby augmenting the indicated ambient light intensity, the light generating means being powered by the voltage difference across the bidirectional switching means whereby the light generating means are actuated to generate light whenever the bidirectional switching means are in a non-conductive state and are inoperative whenever the switching means are in a conductive state.
bidirectional switching means for electrically coupling the two device terminals for conduction of current, the bidirectional switching means being actuated for conduction by the voltage difference between the two device terminals and requiring triggering in each half-cycle of the AC voltage to remain in a conductive state;
a photoresistive element whose resistance varies with the intensity of light incident on the element thereby sensing and indicating ambient light intensity;
triggering means powered by the voltage difference between the two device terminals and responsive to the resistance of the photoresistive element for triggering the bidirectional switching means in each half-cycle of the AC voltage when the indicated ambient light intensity drops below a threshold level; and, light generating means positioned proximate to the light sensing means for generating light of predetermined intensity when actuated thereby augmenting the indicated ambient light intensity, the light generating means being powered by the voltage difference across the bidirectional switching means whereby the light generating means are actuated to generate light whenever the bidirectional switching means are in a non-conductive state and are inoperative whenever the switching means are in a conductive state.
2. A two-terminal device as claimed in claim 1 in which:
the bidirectional switching means comprise a triac with a trigger terminal; and;
the triggering means comprise a voltage divider coupling the two device terminals to produce at a divider node a divider voltage which tends to be a predetermined fraction of the voltage difference between the two device terminals, and a bidirectional semiconductor device with a predetermined turn-on voltage coupling the divider node to the trigger terminal; and, the photoresistive element couples the divider node to a first of the device terminals thereby reducing the divider voltage.
the bidirectional switching means comprise a triac with a trigger terminal; and;
the triggering means comprise a voltage divider coupling the two device terminals to produce at a divider node a divider voltage which tends to be a predetermined fraction of the voltage difference between the two device terminals, and a bidirectional semiconductor device with a predetermined turn-on voltage coupling the divider node to the trigger terminal; and, the photoresistive element couples the divider node to a first of the device terminals thereby reducing the divider voltage.
3. A two-terminal device as claimed in claim 2 for series connection with an incandescent lighting element, comprising:
a resistor series coupling the photoresistive element to the first device terminal;
a two-terminal diode-type device;
a rotary switch having ten poles equally spaced-apart circumferentially in a circular arrangement and a rotatable wiper with a pair ofdiametrically opposing, conductive wiper end portions, one wiper end portion electrically connecting one adjacent pair of poles whenever the other wiper end portion electrically connects another adjacent pair of poles diametrically opposite to the one adjacent pair of poles;
the diode-type device electrically coupling a circumferentially first pole and a circumferentially fifth pole, the circumferentially fifth pole being electrically coupled to the second device terminal;
a circumferentially second pole being electrically coupled to the first end of the photoresistive element and to a circumferentially seventh pole;a circumferentially third pole being electrically coupled to the first device terminal whereby connection of the circumferentially second and third terminal by one of the wiper end portions shorts the resistor;
circumferentially fourth, eighth, ninth and tenth poles being electrically coupled together.
a resistor series coupling the photoresistive element to the first device terminal;
a two-terminal diode-type device;
a rotary switch having ten poles equally spaced-apart circumferentially in a circular arrangement and a rotatable wiper with a pair ofdiametrically opposing, conductive wiper end portions, one wiper end portion electrically connecting one adjacent pair of poles whenever the other wiper end portion electrically connects another adjacent pair of poles diametrically opposite to the one adjacent pair of poles;
the diode-type device electrically coupling a circumferentially first pole and a circumferentially fifth pole, the circumferentially fifth pole being electrically coupled to the second device terminal;
a circumferentially second pole being electrically coupled to the first end of the photoresistive element and to a circumferentially seventh pole;a circumferentially third pole being electrically coupled to the first device terminal whereby connection of the circumferentially second and third terminal by one of the wiper end portions shorts the resistor;
circumferentially fourth, eighth, ninth and tenth poles being electrically coupled together.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000494806A CA1264351A (en) | 1985-11-07 | 1985-11-07 | Controlling lighting elements in response to ambient light intensity |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000494806A CA1264351A (en) | 1985-11-07 | 1985-11-07 | Controlling lighting elements in response to ambient light intensity |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1264351A true CA1264351A (en) | 1990-01-09 |
Family
ID=4131822
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000494806A Expired - Lifetime CA1264351A (en) | 1985-11-07 | 1985-11-07 | Controlling lighting elements in response to ambient light intensity |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1264351A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009045173A2 (en) * | 2007-10-02 | 2009-04-09 | Ettanoor Thuppale Mohan Dass | Switching device |
-
1985
- 1985-11-07 CA CA000494806A patent/CA1264351A/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009045173A2 (en) * | 2007-10-02 | 2009-04-09 | Ettanoor Thuppale Mohan Dass | Switching device |
| WO2009045173A3 (en) * | 2007-10-02 | 2010-12-23 | Ettanoor Thuppale Mohan Dass | Switching device |
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| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |