CA1071699A - Control circuit for progressively varying illumination intensity of lamps - Google Patents
Control circuit for progressively varying illumination intensity of lampsInfo
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- CA1071699A CA1071699A CA243,597A CA243597A CA1071699A CA 1071699 A CA1071699 A CA 1071699A CA 243597 A CA243597 A CA 243597A CA 1071699 A CA1071699 A CA 1071699A
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- 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
Abstract
ABSTRACT OF THE DISCLOSURE:
A control circuit for progressively and gradually varying the illumination intensity of incandescent lamps.
The circuit comprises a source of alternating current connected in series with an electric lamp load which is also in series with a silicon controlled rectifier. This silicon control rectifier is rendered conductive when its gate is actuated by a gate signal generated by a programmable unijunction transistor (PUT). The conduction of the PUT depends on the voltage applied on its gate by a gate biasing circuit connected thereto and which comprises a charging capacitor. On the other hand, a charging circuit is connected across the silicon control rec-tifier whereas a second charging circuit is connected between the anode of the PUT and the first-mentioned charging circuit.
Thus, progressive and gradual extinction or quenching as well as progressive and gradual ignition or lightening of the electric lamp are effected by making the charging or discharging time of the first-mentioned circuit higher than the charging or discharging time of the gate biasing circuit, whereby the time intervals between which the PUT is made conductive becomes longer and longer due to the reducing difference between the voltage supplied by the biasing circuit to the gate of the PUT and the voltage on the cathode of the PUT supplied by the second-mentioned char-ging circuit, at each source cycle.
A control circuit for progressively and gradually varying the illumination intensity of incandescent lamps.
The circuit comprises a source of alternating current connected in series with an electric lamp load which is also in series with a silicon controlled rectifier. This silicon control rectifier is rendered conductive when its gate is actuated by a gate signal generated by a programmable unijunction transistor (PUT). The conduction of the PUT depends on the voltage applied on its gate by a gate biasing circuit connected thereto and which comprises a charging capacitor. On the other hand, a charging circuit is connected across the silicon control rec-tifier whereas a second charging circuit is connected between the anode of the PUT and the first-mentioned charging circuit.
Thus, progressive and gradual extinction or quenching as well as progressive and gradual ignition or lightening of the electric lamp are effected by making the charging or discharging time of the first-mentioned circuit higher than the charging or discharging time of the gate biasing circuit, whereby the time intervals between which the PUT is made conductive becomes longer and longer due to the reducing difference between the voltage supplied by the biasing circuit to the gate of the PUT and the voltage on the cathode of the PUT supplied by the second-mentioned char-ging circuit, at each source cycle.
Description
The present invention relates to circuits for con-trolling the illumination intensity of electric incandescent lamps or the like.
More particularly, the present invention is relative to a circuit especially adapted to vary in a graduaI ana pro-gressive fashion the illumination intensity of the light radiated by electric lamps by controlling the amount of electric current flowing through the incandescent loads of the lamps. According to this invention, the circuit thus allows the lamp illumination intensity to change gradually and progressively from full bright-ness to complete extinction and thereupon to return gradually and progressively to its full brightness condition, this on-off cycle being furthermore automatically resumed.
Several circuits are known in the art to perform the turning on and off, in a cyclical manner, electric lamps or bulbs. For example,such prior circuits are described in , U.S. Patent No. 3,265,907 issued on August 9, 1966 to Xurata et al; in U.S. Patent No. 3,300,711 delivered on January 24, 1967 to Duncan; in U.S. Patent No.3,331,013 issued on July 11, 1967 to Cunningham; in U.S. Patent No, 3,358,186 delivered to Nomura on December 12, 1967; in U.S. Patent Not 3,728,713 issued on April 17, 1973 to Alten; in U.S. Patent No. 3,737,731 delivered to Zeewy on June 5, 1973; and U.S. Patent No. 3,753,039 issued on August 14,1973 to Bonazoli et al. Those known circuits are useful for controlling the alternating or continuous current supplied to lamp loads, but in an instantaneous fashion, and ; ~ are therefore commonly labelled as dimming or flashing circuits and consequently they cannot be used for the purpose of progres-sively and gradually varying the illumination intensity of lamps.
~30 A prime object of the present inventilon resides in circuit for progressively and gradually varying the illumina-tion intensity of electric lamps through controlling the current ., j .
' , ~' ,, ~ ;~
. . ' . ~
1(~7~69~
intensity flowing through the lamp loads.
A particular application of the circuit according to this invention, consists in creating varying light illumi-nation effects onto or in conjunction~ith any advertisement means constituted, for instance, of graphic illustrations, dia-grams or designs, for the purpose o~ attracting people's eyes or of producing pleasant luminous effects. In this respect, a particularly outstanding and pleasant effect is produced when colored lamps or bulbs are utilized, the illumination brightness of which is progressively and gradually varied, especially when several circuits of the type according to the present invention are employed. The several circuits are then preferably parallely interconnected and each circuit will serve to progres-sively light on and off one or more lamps of a different color to create continuously moving light patterns of various color effects owing to the intermixing of the light color of the various lamps utilized. This moving light color effect is par-ticularly emphasized when one or more lamps of a given color, associa,ted with a control circuit in accordance with the present invention, are progressively turned on and off at tlme intervals different from the time intervals of the other parallely connec-ted circuits associated each with lamps of other colors. Such outphasing in the energization of lamps of various colors thereby results in producing moving light patterns not only composed of the basic color o the individual lamps but also of colors modulated by the nature and the brightness of two ox more differently colored lamps. As a result, a li~ht pattern of continuously varying and moving colors is effectively produced.
Another object of the present invention therefore resi-des in creating a light pattern of continuously varying and moving colors by using two or more parallely connected circuits wherein each circuit is adapted to eneryize lamps of a given color to 1~317~6~9 control the ill~lmination intensity thereof in a progressive and gradual manner and according to a time interval which is diffe-rent from time intervals at which the lamps of other colors asso-; ciated with ~the ather ;circuits are energized.
Therefore, the circuit in accordance with the presentinvention comprises a source of alternating current connected in series with an electric lamp load which is also in series with a silicon controlled rectifier. This silicon control rectifier is rendered conductive when its gate is actuated by a gate signal generated by a programmable unijunction transistor (PUT). The conduction of the PUT depends on the voltage applied on its gata by a gate biasing circuit connected thereto and which comprises a charging capacitor. On the other hand, a charging circuit is connected across the silicon control rectifier whereas a second charging circuit is connected between the anode of the PUT and the first-mentioned charging circuit. Thus, progressive and gradual extinction or quenching as well as progressive and gradual ignition or lightening of the electric lamp are effec-ted by making the charging or discharging time of the first-mentioned circuit higher than the charging or discharging time of the gate biasing circuit, whereby the time intervals bet-ween which the PUT is made conductive becomes longer and longer due to thè reducing difference between the voltage supplied by the biasing circuit to the gate of the PUT and the voltage on the cathode of the PUT supplied by the second-mentioned charging -circuit, at each source cycle.
Preferred embodiments of the present invention will ; be hereinafter described with reerence to the accompanying drawing, wherein Figure 1 illustrates a schematic diagxam of a light intensity control circuit in accordance with the present inven-; tion; and _ 3 _ ~C~7~L699 Figure 2 shows the spectrum o light colors obtained when utilizing lamps o~ three di~erent colors,where the inten-sity of one or more lamps of a given color is being controlled by one individual circuit of figure 1, three such circuits being so used to produce the desired light effects.
Referring to figure 1, there is shown a circuit in accordance with the present invention able to control illumina-tion intensity of the lamp in order to vary progressively and gradually the current flowing through the lamp load. The circuit is fed with alternating current through terminals "A" and "B", the current supply source being any convention and standard.
mains such as of 110 volts at 60 hertz. An incandescent lamp '!L"
has one of its load termlnals connected to input terminal "A"
when on-off switch 'S" ~ closed and the other terminal connected to the anode "a" of a silicon controlled rectifier SCR the cathode "b" of which is linked to the other input terminal "B". Although .
only a single lamp is illustrated, a plurality of lamps, serial-ly or parallely interconnected, may as well be.utili2ed, the number of lamps being only restricted by the breakdown current characteristics of the SCR.
A programmable unijunction transistor PUT, when conduc-tive, delivers a gate signal through its cathode "f" which is connected to terminal "B" by means o~ a resistor R8. The voltage drop in resistor R8 triggers the gate "c" of the SCR which then becomes conductive. It is to be noted that the value of resistor ~:
R8 in the trigger circuit is kept low enough to prevent the DC
voltage at the gate from exceeding the minimum gate triggering voltage for the:SCR, in order to avoid excessive interbase current ~in the SCR. As noted, the PUT is in .its conduction state whenever the voltage and its anode "e'l exceeds the voltage on the gate electrode "g"/ the PVT being otherwise in a non-conduction ~ ~ . ' ' state. The gate "g" is serially connected to a voltage divider formed of resistors R4 and R5 and the junction point of resistors R4 and R5 is connected to the gate charging circuit "G" through diode~D3. Th-i~s gate biiasing.circuit "G" is constituted of an electrolytic capacitor C connected across series resistors R
and R7 and has a charging time which is determined by capacitor C3 and resistors R6 and R7. Thus, the charging of capacitor C3 will, on the one hand, increase the voltage applied on gate "g" of the PUT whereas the discharging of C3 through resistors ¦
R6 and R7 will, on the other hand, provoke a decrease of the PUT
gate voltage. In order to set the charging and discharging time . .
; of a circuit "G" to a desired value, the resistor R7 is made variable and has its wiper directly connected to terminal "B". 1 :
As mentioned previously, the PUT is conductive whenever ¦:
the difference between thé anode voltage and the gate voltage . thereon is positive, which means th~ the voltage at junction ; point "C" has to exceed the gate voltage generated by circuit "G"
to cause conduction of the PUT. To produce the required voltage at junction "C", a charging circuit "H", having a charging time determined by serially connected capacitor Cl and resistor R , is provided in parallel with the SCR terminals; and so is another ~ .
charging circuit "I" constituted of capacitor C2 in parallel with resistor R2. This circuit "I" is, on the one hand, connected ~ to the junction terminal of resistor Rl and capacitor Cl and, `~ on the other hand, connected to the cathode of diode D2 the anode ~.
of which is linked to the anode of PUT at "C". A current limi-ting resistor R3 is connected between terminal"C"and the junction , ` terminal of a half-wave rectifying diode D1 having its anode con-nected to resistor R1, and to resistor R4.
An important characteristic of the control circuit shown in figure lresides in the proper determination of the charging and discharging time of circuit "H". Indeed, it ha~
1~7~6~9 been found that progressive and gradual illumination of lamp~L~' is effectively achieved when ~he charging and discharging time o~ charging circuit "H" substantially exceeds the charging and discharging time of biasing circui~ ~G", ~ha~di-~~rence ~n charging times defining the time intervals during which the PUT
is in its conduction or non-conduction state. Thus, by making the charging time of circuit "G" lower than that of circuit "H", the rate at which the voltage build up ~ the gate electrode of hlgh~*
~ the PUT is kept ~ew4~ than the rate at which the PUT anode volt~ge ;10 is increasing, thereby properly controlling the time interval aefining conduction or non-conduction of the PUT and hence the illumination intensity of lamp L in terms of current flowing through its resistive load.
~ Initially, each capacitor Cl, C2 and C3 is uncharged,- and, upon actuation of switch"S', an alternating voltage is sup plied to the control circuit of figure 1. Then, capacitor C2 of charging circuit "I" is rapidly charged and a positive vol-tage is impress~d upon the anode of the PUT which thus becomes conductive. A gate signal is generated at the cathode of the PUT to trigger the gate electrode of the SCR and to cause a current flowing through the load of lamp L which is then illu-minated to its full brightness. On the other hand, charges are building up on capacitors Cl and C3 so that the voltage diffe-rence between the anode voltage and gate voltage of the PUT is constantly decreasing until the PUT is fully and co~ let~ly tur-ned off. Moreover, as capacitor Cl is charged more rapidly than capacitor C3, owing to the respective charging time of circuits '~"and'~",the turning~on time of the P~T is delayed at each suc-cessive source cycle, thereby gradually and progressively, decrea-sing the illumination intensity of the lamp "L" until its com-plete extinction is reached. The PUT being in its non-conduction state, the capacitors Cl and C3 are discharged. But~ owing to , .......... ~ , ;9~
their respective time constant, the capacitor Cl is discharging at a rate exceeding that of capacitor C , and therefore the Pu~
becomes conductive and serves to unblock the SCR. And, as the ~oltage diff-er.ence,betweenthe.anode ~oltage and the gate~v~l~age of the PUT is progressively increasing, the time interval during whichthe PUT is non-conductive becomes smaller and smaller and hence, the lightening of the lamp "L" is progressively and gradually increased to full brightness. Thereupon, the progres- .:
.sive extinction and lightening operation of the lamp is automa- , tically resumed following the above-described operation cycle.
It appears in order to indicate the typical experi-mental values of the components used in the circuitry shown in figure 1, which are as follows:
Rl - 220 Kohms R2 - ~2 Kohms R3 = 100 Kohms '.
R4 = 196 Kohms R5 = 100 Kohms R6 ~ 200 Kohms R7 - 0 - 100 Kohms R8 z 1 Kohm Cl Z 50~F, 50 V
C2 = lO,uF, 10 V
C3 _ lO~F, 50 V
SCR ~ type ECG 5455 made by General Electric Company PUT = type ECG 6502 made by ~eneral Electric Company Dl, D2 and D3 - type lN 5393 made by General Electric Company Each single control circuit shown in ,Figure 1, is able to produce oneof the light waves illustrated in Figure 2. The particular purpose of Figure 2 resides in illustrating an especial-ly interesting application of the basic circuit in accordance ..
~ID716~9 with the present invention when, for instance, three such circuits are used in parallel, each serving to control the illu-mlnation intensity of a lamp or group of lamps of a specific colo.r.. .So, when three circuits are used to progressively and gradually energize and deenergize blue lamps, green lamps and yellow lamps, respectively, a continuously varying and moving pattern of light colors results due to the continuous mixing and modulation of the three basic colors, the intensity and energi-zation time of which individually vary in time. The operation cycle of each individual circuit, and thus the illumination cycles of the lamps associated with one circuit, is made diffe-rent from that of the other circuits merely by setting the value of the variable resistor R7 of the biasing circuit "G" so as to particularize the time constant of that circuit "G". Obviously, the resulting-spectrum of light colors may be varied at infinity since the illumination cycle of each circuit essentially relies upon a given value selected on variable resistor R .
It is understood that the above description is not cons-trued to be limitative, but that several modifications to the described embodiments could be made without departing from the scope of the present invention which is defined in the following claims.
~ ' .
. ,. - . .. : . , , ` - . , ' .
More particularly, the present invention is relative to a circuit especially adapted to vary in a graduaI ana pro-gressive fashion the illumination intensity of the light radiated by electric lamps by controlling the amount of electric current flowing through the incandescent loads of the lamps. According to this invention, the circuit thus allows the lamp illumination intensity to change gradually and progressively from full bright-ness to complete extinction and thereupon to return gradually and progressively to its full brightness condition, this on-off cycle being furthermore automatically resumed.
Several circuits are known in the art to perform the turning on and off, in a cyclical manner, electric lamps or bulbs. For example,such prior circuits are described in , U.S. Patent No. 3,265,907 issued on August 9, 1966 to Xurata et al; in U.S. Patent No. 3,300,711 delivered on January 24, 1967 to Duncan; in U.S. Patent No.3,331,013 issued on July 11, 1967 to Cunningham; in U.S. Patent No, 3,358,186 delivered to Nomura on December 12, 1967; in U.S. Patent Not 3,728,713 issued on April 17, 1973 to Alten; in U.S. Patent No. 3,737,731 delivered to Zeewy on June 5, 1973; and U.S. Patent No. 3,753,039 issued on August 14,1973 to Bonazoli et al. Those known circuits are useful for controlling the alternating or continuous current supplied to lamp loads, but in an instantaneous fashion, and ; ~ are therefore commonly labelled as dimming or flashing circuits and consequently they cannot be used for the purpose of progres-sively and gradually varying the illumination intensity of lamps.
~30 A prime object of the present inventilon resides in circuit for progressively and gradually varying the illumina-tion intensity of electric lamps through controlling the current ., j .
' , ~' ,, ~ ;~
. . ' . ~
1(~7~69~
intensity flowing through the lamp loads.
A particular application of the circuit according to this invention, consists in creating varying light illumi-nation effects onto or in conjunction~ith any advertisement means constituted, for instance, of graphic illustrations, dia-grams or designs, for the purpose o~ attracting people's eyes or of producing pleasant luminous effects. In this respect, a particularly outstanding and pleasant effect is produced when colored lamps or bulbs are utilized, the illumination brightness of which is progressively and gradually varied, especially when several circuits of the type according to the present invention are employed. The several circuits are then preferably parallely interconnected and each circuit will serve to progres-sively light on and off one or more lamps of a different color to create continuously moving light patterns of various color effects owing to the intermixing of the light color of the various lamps utilized. This moving light color effect is par-ticularly emphasized when one or more lamps of a given color, associa,ted with a control circuit in accordance with the present invention, are progressively turned on and off at tlme intervals different from the time intervals of the other parallely connec-ted circuits associated each with lamps of other colors. Such outphasing in the energization of lamps of various colors thereby results in producing moving light patterns not only composed of the basic color o the individual lamps but also of colors modulated by the nature and the brightness of two ox more differently colored lamps. As a result, a li~ht pattern of continuously varying and moving colors is effectively produced.
Another object of the present invention therefore resi-des in creating a light pattern of continuously varying and moving colors by using two or more parallely connected circuits wherein each circuit is adapted to eneryize lamps of a given color to 1~317~6~9 control the ill~lmination intensity thereof in a progressive and gradual manner and according to a time interval which is diffe-rent from time intervals at which the lamps of other colors asso-; ciated with ~the ather ;circuits are energized.
Therefore, the circuit in accordance with the presentinvention comprises a source of alternating current connected in series with an electric lamp load which is also in series with a silicon controlled rectifier. This silicon control rectifier is rendered conductive when its gate is actuated by a gate signal generated by a programmable unijunction transistor (PUT). The conduction of the PUT depends on the voltage applied on its gata by a gate biasing circuit connected thereto and which comprises a charging capacitor. On the other hand, a charging circuit is connected across the silicon control rectifier whereas a second charging circuit is connected between the anode of the PUT and the first-mentioned charging circuit. Thus, progressive and gradual extinction or quenching as well as progressive and gradual ignition or lightening of the electric lamp are effec-ted by making the charging or discharging time of the first-mentioned circuit higher than the charging or discharging time of the gate biasing circuit, whereby the time intervals bet-ween which the PUT is made conductive becomes longer and longer due to thè reducing difference between the voltage supplied by the biasing circuit to the gate of the PUT and the voltage on the cathode of the PUT supplied by the second-mentioned charging -circuit, at each source cycle.
Preferred embodiments of the present invention will ; be hereinafter described with reerence to the accompanying drawing, wherein Figure 1 illustrates a schematic diagxam of a light intensity control circuit in accordance with the present inven-; tion; and _ 3 _ ~C~7~L699 Figure 2 shows the spectrum o light colors obtained when utilizing lamps o~ three di~erent colors,where the inten-sity of one or more lamps of a given color is being controlled by one individual circuit of figure 1, three such circuits being so used to produce the desired light effects.
Referring to figure 1, there is shown a circuit in accordance with the present invention able to control illumina-tion intensity of the lamp in order to vary progressively and gradually the current flowing through the lamp load. The circuit is fed with alternating current through terminals "A" and "B", the current supply source being any convention and standard.
mains such as of 110 volts at 60 hertz. An incandescent lamp '!L"
has one of its load termlnals connected to input terminal "A"
when on-off switch 'S" ~ closed and the other terminal connected to the anode "a" of a silicon controlled rectifier SCR the cathode "b" of which is linked to the other input terminal "B". Although .
only a single lamp is illustrated, a plurality of lamps, serial-ly or parallely interconnected, may as well be.utili2ed, the number of lamps being only restricted by the breakdown current characteristics of the SCR.
A programmable unijunction transistor PUT, when conduc-tive, delivers a gate signal through its cathode "f" which is connected to terminal "B" by means o~ a resistor R8. The voltage drop in resistor R8 triggers the gate "c" of the SCR which then becomes conductive. It is to be noted that the value of resistor ~:
R8 in the trigger circuit is kept low enough to prevent the DC
voltage at the gate from exceeding the minimum gate triggering voltage for the:SCR, in order to avoid excessive interbase current ~in the SCR. As noted, the PUT is in .its conduction state whenever the voltage and its anode "e'l exceeds the voltage on the gate electrode "g"/ the PVT being otherwise in a non-conduction ~ ~ . ' ' state. The gate "g" is serially connected to a voltage divider formed of resistors R4 and R5 and the junction point of resistors R4 and R5 is connected to the gate charging circuit "G" through diode~D3. Th-i~s gate biiasing.circuit "G" is constituted of an electrolytic capacitor C connected across series resistors R
and R7 and has a charging time which is determined by capacitor C3 and resistors R6 and R7. Thus, the charging of capacitor C3 will, on the one hand, increase the voltage applied on gate "g" of the PUT whereas the discharging of C3 through resistors ¦
R6 and R7 will, on the other hand, provoke a decrease of the PUT
gate voltage. In order to set the charging and discharging time . .
; of a circuit "G" to a desired value, the resistor R7 is made variable and has its wiper directly connected to terminal "B". 1 :
As mentioned previously, the PUT is conductive whenever ¦:
the difference between thé anode voltage and the gate voltage . thereon is positive, which means th~ the voltage at junction ; point "C" has to exceed the gate voltage generated by circuit "G"
to cause conduction of the PUT. To produce the required voltage at junction "C", a charging circuit "H", having a charging time determined by serially connected capacitor Cl and resistor R , is provided in parallel with the SCR terminals; and so is another ~ .
charging circuit "I" constituted of capacitor C2 in parallel with resistor R2. This circuit "I" is, on the one hand, connected ~ to the junction terminal of resistor Rl and capacitor Cl and, `~ on the other hand, connected to the cathode of diode D2 the anode ~.
of which is linked to the anode of PUT at "C". A current limi-ting resistor R3 is connected between terminal"C"and the junction , ` terminal of a half-wave rectifying diode D1 having its anode con-nected to resistor R1, and to resistor R4.
An important characteristic of the control circuit shown in figure lresides in the proper determination of the charging and discharging time of circuit "H". Indeed, it ha~
1~7~6~9 been found that progressive and gradual illumination of lamp~L~' is effectively achieved when ~he charging and discharging time o~ charging circuit "H" substantially exceeds the charging and discharging time of biasing circui~ ~G", ~ha~di-~~rence ~n charging times defining the time intervals during which the PUT
is in its conduction or non-conduction state. Thus, by making the charging time of circuit "G" lower than that of circuit "H", the rate at which the voltage build up ~ the gate electrode of hlgh~*
~ the PUT is kept ~ew4~ than the rate at which the PUT anode volt~ge ;10 is increasing, thereby properly controlling the time interval aefining conduction or non-conduction of the PUT and hence the illumination intensity of lamp L in terms of current flowing through its resistive load.
~ Initially, each capacitor Cl, C2 and C3 is uncharged,- and, upon actuation of switch"S', an alternating voltage is sup plied to the control circuit of figure 1. Then, capacitor C2 of charging circuit "I" is rapidly charged and a positive vol-tage is impress~d upon the anode of the PUT which thus becomes conductive. A gate signal is generated at the cathode of the PUT to trigger the gate electrode of the SCR and to cause a current flowing through the load of lamp L which is then illu-minated to its full brightness. On the other hand, charges are building up on capacitors Cl and C3 so that the voltage diffe-rence between the anode voltage and gate voltage of the PUT is constantly decreasing until the PUT is fully and co~ let~ly tur-ned off. Moreover, as capacitor Cl is charged more rapidly than capacitor C3, owing to the respective charging time of circuits '~"and'~",the turning~on time of the P~T is delayed at each suc-cessive source cycle, thereby gradually and progressively, decrea-sing the illumination intensity of the lamp "L" until its com-plete extinction is reached. The PUT being in its non-conduction state, the capacitors Cl and C3 are discharged. But~ owing to , .......... ~ , ;9~
their respective time constant, the capacitor Cl is discharging at a rate exceeding that of capacitor C , and therefore the Pu~
becomes conductive and serves to unblock the SCR. And, as the ~oltage diff-er.ence,betweenthe.anode ~oltage and the gate~v~l~age of the PUT is progressively increasing, the time interval during whichthe PUT is non-conductive becomes smaller and smaller and hence, the lightening of the lamp "L" is progressively and gradually increased to full brightness. Thereupon, the progres- .:
.sive extinction and lightening operation of the lamp is automa- , tically resumed following the above-described operation cycle.
It appears in order to indicate the typical experi-mental values of the components used in the circuitry shown in figure 1, which are as follows:
Rl - 220 Kohms R2 - ~2 Kohms R3 = 100 Kohms '.
R4 = 196 Kohms R5 = 100 Kohms R6 ~ 200 Kohms R7 - 0 - 100 Kohms R8 z 1 Kohm Cl Z 50~F, 50 V
C2 = lO,uF, 10 V
C3 _ lO~F, 50 V
SCR ~ type ECG 5455 made by General Electric Company PUT = type ECG 6502 made by ~eneral Electric Company Dl, D2 and D3 - type lN 5393 made by General Electric Company Each single control circuit shown in ,Figure 1, is able to produce oneof the light waves illustrated in Figure 2. The particular purpose of Figure 2 resides in illustrating an especial-ly interesting application of the basic circuit in accordance ..
~ID716~9 with the present invention when, for instance, three such circuits are used in parallel, each serving to control the illu-mlnation intensity of a lamp or group of lamps of a specific colo.r.. .So, when three circuits are used to progressively and gradually energize and deenergize blue lamps, green lamps and yellow lamps, respectively, a continuously varying and moving pattern of light colors results due to the continuous mixing and modulation of the three basic colors, the intensity and energi-zation time of which individually vary in time. The operation cycle of each individual circuit, and thus the illumination cycles of the lamps associated with one circuit, is made diffe-rent from that of the other circuits merely by setting the value of the variable resistor R7 of the biasing circuit "G" so as to particularize the time constant of that circuit "G". Obviously, the resulting-spectrum of light colors may be varied at infinity since the illumination cycle of each circuit essentially relies upon a given value selected on variable resistor R .
It is understood that the above description is not cons-trued to be limitative, but that several modifications to the described embodiments could be made without departing from the scope of the present invention which is defined in the following claims.
~ ' .
. ,. - . .. : . , , ` - . , ' .
Claims (8)
1. A circuit for progressively and gradually control-ling an electric current flowing through incandescent lamp loads, comprising:
a source of alternating current, a silicon control rectifier having anode, cathode and gate electrodes, said anode electrode being connected in series with at least one of said lamp loads, both being connected across said source, a programmable unijunction -transistor having anode, cathode and gate electrodes for generating, when made conductive, a gate signal through the cathode thereof to the gate of said silicon control rectifier, a capacitance-resistance biasing circuit connected to the gate of said programmable unijunction transistor, said bia-sing circuit having a first predetermined charging time, a first charging circuit connected between the anode and cathode of said silicon control rectifier and having a second predetermined charging time, a second charging circuit connected to the anode of the programmable unijunction transistor through a diode and to said first charging circuit, the charging time of said first charging circuit being higher than the charging time of said gate biasing circuit so that the current flowing through the lamp load is progressively and gradually decreased at each cycle of said alternating current source till null, and afterwards is increased to its full inten-sity, such increase and decrease in the current intensity being cyclically and automatically resumed.
a source of alternating current, a silicon control rectifier having anode, cathode and gate electrodes, said anode electrode being connected in series with at least one of said lamp loads, both being connected across said source, a programmable unijunction -transistor having anode, cathode and gate electrodes for generating, when made conductive, a gate signal through the cathode thereof to the gate of said silicon control rectifier, a capacitance-resistance biasing circuit connected to the gate of said programmable unijunction transistor, said bia-sing circuit having a first predetermined charging time, a first charging circuit connected between the anode and cathode of said silicon control rectifier and having a second predetermined charging time, a second charging circuit connected to the anode of the programmable unijunction transistor through a diode and to said first charging circuit, the charging time of said first charging circuit being higher than the charging time of said gate biasing circuit so that the current flowing through the lamp load is progressively and gradually decreased at each cycle of said alternating current source till null, and afterwards is increased to its full inten-sity, such increase and decrease in the current intensity being cyclically and automatically resumed.
2. A control circuit as claimed in claim 1, wherein said gate biasing circuit comprises a capacitor connected across a resistor which is in series with a variable resistor the wiper of which is connected to one terminal of said capacitor and to the cathode of said silicon control rectifier, the other terminal of said capacitor being connected to the gate of the programmable unijunction transistor through a second diode and a second resistor, and wherein the first charging circuit comprises a second capaci-tor in series with a third resistor at the junction point of which is connected said second charging circuit.
3. A control circuit as claimed in claim 2, wherein the anode of the silicon control rectifier is connected to the anode of the programmable unijunction transistor through a third diode and a fourth resistor and, wherein the cathode of the sili-con control rectifier is connected to the cathode of the program-mable unijunction transistor through a fifth resistor.
4. A control circuit as claimed in claim 2, wherein a fourth resistor is connected between said second diode and a third diode, and wherein said second charging circuit comprises a third capacitor in parallel with a fifth resistor.
5. A circuit for progressively and gradually control-ling an electric current flowing through color lamp loads by means of parallely connected circuit units fed by a common source of alternating current, each circuit unit comprising a silicon control rectifier having anode, cathode and gate electrodes, said anode electrode being connected in series with at least one of said lamp loads, both being connected across said source, a programmable unijunction transistor having anode, cathode and gate electrodes for generating, when made conductive, a gate signal through the cathode thereof to the gate of said silicon control rectifier, a capacitance-resistance biasing circuit connected to the gate of said programmable unijunction transistor, said bia-sing circuit having a first predetermined charging time, a first charging circuit connected between the anode and cathode of said silicon control rectifier and having a second predetermined charging time, a second charging circuit connected to the anode of the programmable unijunction transistor through a diode and to said first charging circuit, the charging time of said first charging circuit being, in each circuit unit, higher than the charging time of said gate biasing circuit whereas the charging time of each biasing circuit is different from that of the second charging circuits, so that the current flowing through the lamp load in each circuit unit is progressively and gradually decreased at each cycle of said alternating current source till null, and afterwards is increased to its full intensity, such increase and decrease in the current intensity being cyclically different for each circuit unit and automatically resumed for all circuit units.
6. A control circuit as claimed in claim 5, wherein said gate biasing circuit comprises a capacitor connected across a resistor which is in series with a variable resistor of a value which differs in each circuit unit and the wiper of which is connected to one terminal of said capacitor and to the cathode of said silicon control rectifier, the other terminal of said capa-citor being connected to the gate of the programmable unijunction transistor through a second diode and a second resistor, and where-in the first charging circuit comprises a second capacitor in se-ries with a third resistor at the junction point of which is connected said second charging circuit.
7. A control circuit as claimed in claim 6, wherein the anode of the silicon control rectifier is connected to the anode of the programmable unijunction transistor through a third diode and a fourth resistor and, wherein the cathode of the silicon control rectifier is connected to the cathode of the pro-grammable unijunction transistor through a fifth resistor.
8. A control circuit as claimed in claim 7, wherein said fourth resistor is connected between said second diode and said third diode, and wherein said second charging circuit com-prises a third capacitor in parallel with a sixth resistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA243,597A CA1071699A (en) | 1976-01-12 | 1976-01-12 | Control circuit for progressively varying illumination intensity of lamps |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA243,597A CA1071699A (en) | 1976-01-12 | 1976-01-12 | Control circuit for progressively varying illumination intensity of lamps |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1071699A true CA1071699A (en) | 1980-02-12 |
Family
ID=4104987
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA243,597A Expired CA1071699A (en) | 1976-01-12 | 1976-01-12 | Control circuit for progressively varying illumination intensity of lamps |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1071699A (en) |
-
1976
- 1976-01-12 CA CA243,597A patent/CA1071699A/en not_active Expired
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