Abstract:
A method, apparatus and system for electrical simulation of a flame that provides for the projection of light that is a mixture of at least two colors. At least one of the two colors of light is projected over time according to a complex light intensity pattern. The complex light intensity pattern is constructed via an aggregation (superimposition) of a plurality of independent intensity transition signals. Each intensity transition signal represents a separate and varying intensity pattern. The complex light intensity pattern creates a perceptually real and pleasing visual effect upon the human eye, much like that created by the flickering of a real combustion flame and employs other than random or pseudo random intensity patterns.

Description:
FIELD OF THE INVENTION 
   This invention relates generally to an apparatus configured for electrical simulation of a flame, and in particular for simulation of a candle flame. 
   BACKGROUND OF THE INVENTION 
   The visual appearance of a flame is often pleasing to the human eye in some circumstances. Establishment and maintenance of a real combustion flame can be inconvenient and can create a significant safely risk to people and things located near it. As an alternative, an electrical simulation of a combustion flame can provide much of the visual effect of a combustion flame with less inconvenience and with substantially less risk to the safety of people and things located near it. 
   SUMMARY OF THE INVENTION 
   The invention provides for a method, apparatus and system for electrical simulation of a flame. In one aspect, the invention provides for the projection of light that is a mixture of at least two colors. At least one of the two colors of light is projected over time according to a complex light intensity pattern. The complex light intensity pattern is constructed via an aggregation (superimposition) of a plurality of independent intensity transition signals. Each intensity transition signal represents a separate and varying intensity pattern. 
   The complex light intensity pattern creates a perceptually real and pleasing visual effect upon the human eye, much like that created by the flickering of a real combustion flame and employs other than random or pseudo random intensity patterns which typically appear perceptually less real than the electrical simulation provided. 
   In some embodiments, the invention provides at least one lower and one upper light source that each generates light of a different color and of a different intensity pattern over time. Preferably and in some embodiments, the intensity pattern ranges between a dim and a bright light intensity and avoids a zero light intensity at any point in time during flame simulation. This creates a flame flicker pattern that does not “turn off”, even for an imperceptibly small period of time, and that generally creates a more perceptibly real flame. 
   The foregoing as well as other objects, aspects, features, and advantages of the invention will become more apparent from the following description and from the claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The objects and features of the invention can be better understood with reference to the claims and drawings described below. The drawings are not necessarily to scale; the emphasis is instead generally being placed upon illustrating the principles of the invention. Within the drawings, like reference numbers are used to indicate like parts throughout the various views. Differences between like parts may cause those like parts to be each indicated by different reference numbers. Unlike parts are indicated by different reference numbers. 
       FIG. 1  illustrates an embodiment of a candle flame simulator including an arrangement of two light emitting diodes. 
       FIG. 2  illustrates a first embodiment of a five volt supplied electronic circuit configured to generate a supplemental intensity signal that includes a superimposition of four individual intensity transition signals. 
       FIG. 3  illustrates a graphical representation of an example of the four intensity transition signals that can be collectively generated over time by the electrical circuit of  FIG. 2 . 
       FIG. 4  illustrates a second embodiment of a three volt supplied electronic circuit configured to generate a supplemental intensity signal that includes a superimposition of four individual intensity transition signals. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  illustrates an embodiment  100  of a candle flame simulator including an arrangement of two light emitting diodes (LEDs). As shown, a lower light emitting diode (LED)  110  is disposed below an upper light emitting diode (LED)  120 . The lower LED  110  has an upper surface  112  and a lower surface  114  and a longitudinal axis  118  that intersects the upper  112  and lower  114  surfaces. The upper LED  120  has an upper surface  122  and a lower surface  124  and a longitudinal axis  128  that intersects the upper  122  and lower  124  surfaces. 
   In other embodiments, another type of light source, can substitute for either the upper  120  or lower  110  light emitting diode. For example, in some embodiments one or more electro-luminescent display devices function as a light source. In some other embodiments, one or more incandescent lights function as a light source. 
   As shown, the LEDs  110 ,  120  are arranged such that the upper surface  112  of the lower LED  110  is located proximate to the lower surface  124  of the upper LED  120  and that longitudinal axis  118  of the lower LED  110  is substantially aligned with the longitudinal axis  128  of the upper LED  120 . With this arrangement, a substantial portion of light emitted from the upper surface  112  of said lower LED  110  passes through the lower surface  124  of the upper LED  120 . In some embodiments, the upper surface  112  of the lower LED  110  abuts the lower surface  124  of the upper LED  120 . 
   The lower LED  110  has two conductors (legs)  116   a - 116   b  protruding from its lower surface  114  and the upper LED  120  has two conductors (legs)  126   a - 126   b  protruding from its lower surface  124 . The conductors  116   a - 116   b ,  126   a - 126   b  are each also referred to as electrodes  116   a - 116   b ,  126   a - 126   b . Positively charged electric current flows into the lower LED  110  via the supply electrode  116   a  and out of the LED  110  via the return electrode  116   b . Likewise, positively charged electric current flows into the upper LED  120  via the supply electrode  126   a  and out of the LED  120  via the return electrode  126   b.    
   In this embodiment, the lower LED  110  is classified as a (3) millimeter LED and the upper LED  120  is classified as a (5) millimeter LED. Both LEDs  110 ,  120  are configured to receive electric current at less than or equal to (5) volts. In some embodiments, the electrodes (cathodes)  116   a  and  126   a  are electrically connected together and also connected to one source of voltage and positive current. In other embodiments, the electrodes (anodes)  116   b  and  126   b  are electrically connected together and also connected to ground. 
   In some embodiments, the lower LED  110  is substantially a shade of blue and the upper LED  120  is substantially a shade of yellow. Preferably, the shade of blue is of an optical wavelength of approximately 468 nanometers and the shade of yellow is of a optical wave length of approximately 589 nanometers. 
     FIG. 2  illustrates a first embodiment  200  of a five volt supplied electronic circuit configured to generate a supplemental intensity signal that includes a superimposition of four individual intensity transition signals. As shown, the electronic circuit  200 , also referred to as a circuit  200 , includes a (5) volt voltage source  210  supplying positively charged current through a voltage regulator  212  that is configured to maintain its output voltage at (5) volts. 
   The circuit  200  also includes (4) integrated circuit (IC) timer components  220   a - 220   d . In this embodiment, the timer components  220   a - 220   d  are known as 555 timers that are supplied from numerous sources, including but not limited to Motorola and Texas Instruments. The timers  220   a - 220   d  can be implemented using such as NE556 component, which is equivalent to (2) NE555&#39;s sharing the same positive and negative connections. The timers  220   a - 220   d  are electrically connected to the circuit  200  in a standard configuration, known as an “astable” configuration. 
   Each 555 timer  220   a - 220   d , also referred to as timers  220   a - 220   d , has (8) external electrodes, referred to as PINS, that are each identified by a unique number (1-8). A PIN number (1) of the 555 timers  220   a - 220   d  is a ground (common) PIN, a PIN number (2) is a trigger PIN, a PIN number (3) is an output PIN, a PIN number (4) is a reset PIN, a PIN number (5) is a control voltage PIN, a PIN number (6) is a threshold PIN, a PIN number (7) is a discharge PIN and a PIN number (8) is a (positive) supply voltage PIN. 
   The 555 timers  220   a - 220   d  each receive a supply voltage via the supply voltage PIN  236   a - 236   d  (PIN number (8)), that is electrically connected to a voltage supply conductor  250   a  that is connected to an output of the voltage regulator  212 . The discharge PIN  234   a - 234   d  (PIN number (7)) for each timer  220   a - 220   d  is each electrically connected between an upper input resistor  222   a - 222   d  and a lower input resistor  224   a - 224   d . The trigger PIN  232   a - 232   d  (PIN number (2)) and the threshold PIN  230   a - 230   d  (PIN number (6)) are each connected between the lower input resistor  224   a - 224   d  and a capacitor  228   a - 228   d  respectively. Each output PIN  240   a - 240   d  respectively connects each timer  220   a - 220   d  to an output resistor  226   a - 226   d . Each ground PIN  238   a - 238   d  respectively connects each timer  220   a - 220   d  to a voltage return (ground) conductor  250   b.    
   Each timer  220   a - 220   d  is configured to set a voltage on the output PIN  240   a - 240   d  that is equal to (5) volts when the voltage detected by the discharge PIN  234   a - 234   d  is less than or equal to ⅔ of the supply voltage. Each timer  220   a - 220   d  is configured to set a voltage on the output PIN  240   a - 240   d  equal to (0) volts when the voltage detected by the discharge PIN  234   a - 234   d  is greater than or equal to ⅔ of the supply voltage. 
   The output  240   a - 240   d  of each timer  220   a - 220   d  generates an intensity transition signal that causes current to flow or not to flow through each output resistor  226   a - 226   d  respectively, and towards an input  126   a  of the upper LED  120  at a particular time. The upper LED  120  emits light in response to each flow (burst) of current that is supplied into its input  126   a.    
   The lower LED  110  receives current that travels through the voltage supply conductor  250   a  and a resistor  212  via its input conductor  116   a . This current constitutes a first intensity signal received by the lower LED  110 . The intensity of the light emitted from the lower LED  110  over time is a response to the first intensity signal. 
   The upper LED  120  receives via its input conductor  126   a , current that travels through the voltage supply conductor  250   a  and a resistor  214 , and additionally receives current that travels through a supplemental conductor  250   c . The current that travels through the supplemental conductor  250   c  is generated from the outputs  226   a - 226   d  of the (4) timers  220   a - 220   d . The current supplied from the voltage supply conductor  250   a  constitutes a base intensity signal that is received by the upper LED  120 . The current collectively supplied from the outputs  226   a - 226   d  of the (4) timers  220   a - 220   d  merges along the supplemental conductor  250   c  and collectively constitutes a supplemental intensity signal that is received by the upper LED  120 . The supplemental intensity signal is a superimposition of the intensity transition signals that are collectively generated by the (4) timers  220   a - 220   d.    
   The current supplied from the voltage supply conductor  250   a  constitutes a base intensity signal that is received by the upper LED  120 . The current collectively supplied from the outputs  226   a - 226   d  of the (4) timers  220   a - 220   d  merges along the supplemental conductor  250   c  and collectively constitutes a supplemental intensity signal that is received by the upper LED  120 . The supplemental intensity signal is an aggregation (superimposition) of the intensity transition signals that are collectively generated by the (4) timers  220   a - 220   d.    
   The supplemental intensity signal supplied by the supplemental conductor  250   c  merges with the base intensity signal supplied by the voltage supply conductor  250   a  to constitute a second intensity signal. The second intensity signal is a superimposition of the base intensity signal and the supplemental intensity signal. The second intensity signal is received by the upper LED  120  via its input  126   a  conductor. The intensity of the light emitted from the upper LED  120  over time is a response to the second intensity signal. 
   In one particular embodiment, each of the resistors  222   a - 222   d  is configured for 10 Kohms of resistance, resistor  224   a  is configured for 470 Kohms of resistance, resistor  224   b  is configured for 100 Kohms of resistance, resistor  224   c  is configured for 33 Kohms of resistance and resistor  224   d  is configured for 6.8 Kohms of resistance. Each of the resistors  226   a - 226   c  is configured for 680 Ohms of resistance. Resistor  226   d  is configured for 470 Ohms of resistance. Resistor  212  is configured for 1 Kohm and resistor  214  is configured for 150 Ohms of resistance. 
   Also in this particular embodiment, each of the capacitors  228   a - 228   d  are configured for 10 micro-farads of capacitance. Also a first additional capacitor  242  connected between conductors  250   a  and  250   b  and connected at the input (upstream) of the voltage regulator  212  is configured for 0.33 micro-farads. Also a second additional capacitor  244  connected between conductors  250   a  and  250   b  and at the output (downstream) of the voltage regulator  212  is configured for 0.1 micro-farads. The first and second additional capacitors are connected in parallel with respect to each other and with respect to the voltage regulator  212 . The voltage regulator  212  is an L78L05 rated voltage capacitor. 
     FIG. 3  illustrates a graphical representation of an example of the four intensity transition signals that can be collectively generated over time by the electrical circuit of  FIG. 2 . As shown, a vertical (Y) axis indicates an act of generating of an intensity transition signal by a particular timer  220   a - 220   d . A signal generating action of each timer  220   a - 220   d  is represented indicated by the symbols A through D, respectively. A horizontal axis (X) indicates a span of time within which an act of generating an intensity transition signal can occur. 
   For this example, the timer  220   a  generates an intensity transition signal  310 , represented by the row labeled (A)  310 , having a period of approximately 6.5 seconds. Within the 6.5 second signal cycle, the timer  220   a  outputs a signal amplitude equal to (5) volts via its output PIN number (3) for a duration of time approximately equal to 3.3 seconds (fully shown and indicated by a cross-hatch area pattern)  310   a , and then outputs a signal amplitude equal to (0) volts via its output PIN number (3) for a duration of time approximately 3.2 seconds (partially shown and indicated by the absence of an area pattern)  310   b , to complete the 6.5 second signal period. 
   For this example, the timer  220   b  generates an intensity transition signal  320 , represented by the row labeled (B)  320 , having a period of approximately 1.5 seconds. Within the 1.5 second signal cycle, the timer  220   b  outputs a signal amplitude equal to (5) volts via its output PIN number (3) for a duration of time approximately equal to 0.8 seconds (fully shown and indicated by a cross-hatch area pattern)  320   a , and then outputs a signal amplitude equal to (0) volts via its output PIN number (3) for a duration of time approximately 0.7 seconds (fully shown and indicated by the absence of an area pattern)  320   b , to complete the approximately 1.5 second signal period. 
   For this example, the timer  220   c  generates an intensity transition signal, represented by the row labeled (C)  330 , having a period of approximately 0.5 seconds. Within the 0.5 second signal cycle, the timer  220   c  outputs a signal amplitude equal to (5) volts via its output PIN number (3) for a duration of time approximately equal to 0.3 seconds (fully shown and indicated by a cross-hatch area pattern)  330   a , and then outputs a signal amplitude equal to (0) volts via its output PIN number (3) for a duration of time approximately 0.2 seconds (fully shown and indicated by the absence of an area pattern)  330   b , to complete the approximately 0.5 second signal period. 
   For this example, the timer  220   d  generates an intensity transition signal, represented by the row labeled (D)  340 , having a period of approximately 0.2 seconds. Within the 0.2 second signal cycle, the timer  220   d  outputs a signal amplitude equal to (5) volts via its output PIN number (3) for a duration of time approximately equal to 0.15 seconds (fully shown and indicated by a cross-hatch area pattern)  340   a , and then outputs a signal amplitude equal to (0) volts via its output PIN number (3) for a duration of time approximately equal to 0.05 seconds (fully shown and indicated by the absence of an area pattern  340   b ), to complete the approximately 0.2 second signal period. The generation of each intensity transition signal is repeated while simulating a flame. 
   As shown, at a time equal to t 0   350 , all (4) intensity transition signals (A)  310 , (B)  320 , (C)  330  and (D)  340  are at a high amplitude  310   a ,  320   a ,  330   a ,  340   a  and supplying current to the upper LED  120 . In other words, the signals (A)  310 , (B)  320 , (C)  330  and (D)  340  are said to be “high”. At a time equal to t 1   352 , the signals (A)  310  and (B)  320  are high and signals (C)  330  and (D)  340  are low. 
   At a time equal to t 2   354 , signals (A)  310  and (D)  340  are high and signals (B)  320  and (C)  330  are low. At a time equal to t 3   356 , signals (A)  310 , (C)  330  and (D)  340  are high and only signal (B)  320  is low. At a time equal to t 4   358 , only signal (A)  310  is high and signals (B)  320 , (C)  330  and (D)  340  are low. At time equal to t 5   360 , all (4) intensity transition signals (A)  310 , (B)  320 , (C)  330  and (D)  340  are again at a high. At time equal to t 6   362 , all (4) intensity transition signals (A)  310 , (B)  320 , (C)  330  and (D)  340  are low and none of the signals  310 - 340  are high. 
   But notice that the substantially uniform base intensity signal that travels through the conductor  250   a  and mixes (modulates) with the intensity transition signals  310 - 340  before passing through the upper LED  120 . Hence, in this preferred embodiment, the intensity of the upper LED  120  remains equal to a value greater than zero, that of the base intensity signal, so that the intensity of the upper LED  120  dims but not reach an intensity value equal to zero so that the intensity of the upper LED  120  is not turned off at any time during the operation of the upper LED  120 . In other embodiments, the base intensity signal is a non-zero and a substantially varying signal. 
   Likewise, in this preferred embodiment, the intensity of the lower LED  110  (not shown) has a substantially uniform intensity and remains equal to a value greater than zero so that the collective intensity of the LEDs  110 ,  120  dims but not reach an intensity value equal to zero so that the collective intensity of the LEDs  110 ,  120  is not turned off at any time during the operation of the flame simulator  100 . 
   In the above described preferred embodiment, neither the LEDs  110 ,  120  are “intermittent”. Neither of the LEDs intermittently turn on and off like much of the prior art. 
   The duration of each signal period, and the apportionment of its high amplitude and its low amplitude, are configured according to the electronic components connected with each of the 555 timers  220   a - 220   d . As specified by the design of the 555 timers  220   a - 220   d , the high amplitude portion (H) of each signal period is determined by the equation:
 
( H )=(0.693)*(Upper Resistor Resistance+Lower Resistor Resistance)*(Capacitor Capacitance)  a.
 
   The low amplitude portion (L) of each signal period is determined by the equation:
 
( L )=(0.693)*(Lower Resistor Resistance)*(Capacitor Capacitance)  b.
 
   As shown in  FIG. 3 , each signal period for the intensity transition signals (A)  310 , (B)  320 , (C)  330  and (D)  340  is apportioned (divided) between a high amplitude (5 volt) portion and a low amplitude (0 volt) portion. Despite the simplicity of each intensity transition signal waveform, the aggregation of the (A)  310 , (B)  320 , (C)  330  and (D)  340  signal waveforms constructs a complex waveform that does not resemble any of the individual intensity transition signal waveforms  310 - 340 . 
   Referring to  FIG. 2 , for example, with respect to the (A) timer  220   a , if its upper resistor  222   a  has a resistance of 10 kohms and its lower resistor  224   a  has a resistance of 470 kohms, and its capacitor  228   a  has a capacitance of 10 microfarads, then the high amplitude portion (H) and the low amplitude portion (L) of each signal period generated by the timer output is equal to:
 
( H )=(0.693)*(10000 ohms+470,000 ohms)*(0.00001)microfarads=3.32 seconds.
 
( L )=(0.693)*(470,000 ohms)*(0.00001)microfarads=3.26 seconds.
         This yields a signal period equal to (3.32 seconds)+(3.26 seconds)=6.58 seconds.       

   Hypothetically, raising the lower resistor resistance  224   a  to 500,000 ohms alters (H) and (L) to be:
 
( H )=(0.693)*(10000 ohms+500,000 ohms)*(0.00001)microfarads=3.53 seconds.
 
( L )=(0.693)*(500,000 ohms)*(0.00001)microfarads=3.47 seconds.
         This yields a larger signal period equal to approximately 7 seconds.       

   The actual current generated during the generation of the high amplitude portion of an intensity transition signal is dependent upon the resistance value of the output resistor  226   a  for the (A) intensity transition signal  310 , dependent upon the resistance value of the output resistor  226   b  for the (B) intensity transition signal  320 , dependent upon the resistance value of the output resistor  226   c  for (C) intensity transition signal  330 , and dependent upon the resistance value of the output resistor  226   d  for (D) intensity transition signal  340 . 
   For example, if the output resistor  226   a  of the (A) timer  220   a  is configured to have a resistance of 1000 ohms, then the (A) intensity transition signal current would equal ((5 volts/1000 ohms)=0.005 amps) during the high signal amplitude portion  310   a  of the (A) intensity transition signal period and ((0 volts/1000 ohms)=0.0 volts) during the low signal amplitude portion  310   b  of the (A) intensity transition signal period. 
   Likewise for example, if the output resistor  226   c  of the (C) timer  220   c  is configured to have a resistance of 400 ohms, then the (C) intensity transition signal current would equal ((5 volts/400 ohms)=0.0125 amps) during the high signal amplitude portion  330   a  of the (C) intensity transition signal period and (0 volts/1000 ohms=0.0 volts) during the low signal amplitude portion  330   b  of the (A) intensity transition signal period. 
   The current supplied by the first intensity signal for the lower LED  110  travels through the voltage supply conductor  250   a  and through the resistor  212  before entering the lower LED  110  via its input electrode  116   a . The amount of this current supplied by the first intensity signal is approximately equal to 5 volts minus the voltage drop across the lower LED  110 , divided by the resistance value of resistor  212 . 
   For example, when the resistance of the resistor  212  is 1000 ohms and when the voltage drop across the lower LED  110  is about 2.4 volts, then the base intensity signal current is approximately ((5 volts−2.4 volts)/1000 ohms=0.0026 amps). 
   The current supplied by the base intensity signal for the upper LED  120  travels through the voltage supply conductor  250   a  and through the resistor  214  before entering the upper LED  120  via its input electrode  126   a . The amount of this current supplied by the base intensity signal is approximately equal to 5 volts minus the voltage drop across the upper LED  120 , divided by the resistance value of resistor  214 . 
   For example, when the resistance of the resistor  214  is 150 ohms and when the voltage drop across the upper LED  120  is about 2.4 volts, then the base intensity signal current is approximately ((5 volts−2.4 volts)/150 ohms=0.017 amps). 
     FIG. 4  illustrates an alternative embodiment  400  of a three volt supplied electronic circuit configured to generate a supplemental intensity signal that includes a superimposition of four individual intensity transition signals. As shown, the electronic circuit  400 , also referred to as a circuit  400 , includes a (3) volt voltage source supplying positively charged current to the lower LED  110  and to the upper LED  120 . 
   The flow of current through the lower LED  110  is restricted (limited) by a resistor  412 , located downstream of the lower LED  110 . This flow of current constitutes a first intensity signal received by the lower LED  110 . Also, the flow of current through the upper LED  120  is restricted (limited) by a resistor  414 . This flow of current constitutes a base intensity signal received by the upper LED  120 . 
   The circuit  400  also includes (4) integrated circuit (IC) 555 timer components  220   a - 220   d  as shown in  FIG. 2 . As described in  FIG. 2 , the timer components  220   a - 220   d  are known as 555 timers that are supplied from numerous sources, including but not limited to Motorola and Texas Instruments. 
   However, in contrast to  FIG. 2 , the timers  220   a - 220   d  are electrically connected to the circuit  400  differently than the timers  220   a - 220   d  shown in  FIG. 2  and in a non-standard configuration. In this non-standard configuration, the timers  220   a - 220   d  collectively drain current at a circuit location  452  downstream of the output of the upper LED  120 . The timers  220   a - 220   d  do not supply current to the input (upstream) of the upper LED  120  as described for  FIG. 2 . In response to draining current at the output (downstream) of the upper LED  120 , more current is be supplied to the upper LED  120 . 
   As described with respect to  FIG. 2 , each timer  220   a - 220   d  has (8) external electrodes, referred to as PINS, that are each identified by a unique number (1-8). The 555 timer PIN number (1) is a ground (common) PIN, PIN number (2) is a trigger PIN, PIN number (3) is an output PIN, PIN number (4) is a reset PIN, PIN number (5) is a control voltage PIN, PIN number (6) is a threshold PIN, PIN number (7) is a discharge PIN and PIN number (8) is a (positive) supply voltage PIN. 
   The 555 timers  220   a - 220   d  each receive a supply voltage (Vcc) via the supply voltage PIN  460   a - 460   d  (PIN number (8)). The discharge PIN  436   a - 436   d  (PIN number (8)) for each timer  220   a - 220   d  is electrically connected to the voltage drain conductor  450 . The voltage drain conductor is electrically connected at circuit location  452  which is downstream of the output of the upper LED  120 . 
   Each timer  220   a - 220   d  is configured to set a voltage on the output PIN  440   a - 440   d  (PIN number 3) to (5) volts when the voltage measured downstream of an output resistor  426   a - 426   d  is less than or equal to ⅔ of the supply voltage. as detected by the discharge PIN (PIN number (7)). Each timer  220   a - 220   d  is configured to set a voltage on the output PIN  440   a - 440   d  to (0) volts when the voltage measured downstream of the output resistor  426   a - 426   d  is greater than or equal to ⅔ of the supply voltage. as detected by the discharge PIN (PIN number (7)). 
   The output resistor  426   a - 426   d  is located in series with and downstream (with respect to the flow of positive current) of the output PIN  440   a - 440   d  (PIN number 3). The trigger PIN  232   a - 232   d  (PIN number (2)) and the threshold PIN  230   a - 230   d  (PIN number (6)) are each connected on a downstream side of the output resistor  426   a - 426   d  for detection of voltage at that circuit location. Each ground PIN  438   a - 438   d  respectively connects each timer  220   a - 220   d  to a ground potential. 
   The output  440   a - 440   d  of each timer  220   a - 220   d  generates an intensity transition signal that causes current to flow or not to flow through each output resistor  426   a - 426   d  respectively, and towards a capacitor  428   a - 428   d  at particular points in time. The current flowing through the output resistor  426   a - 426   d  is being drawn by the timer  220   a - 220   d  from a circuit location  452  located downstream of the upper LED  120 , causing additional current to flow through the upper LED  120 . When the amplitude of each output PIN  440   a - 440   d  (PIN number 3) is high (5 volts), current and charge flows into and is stored by the capacitor  428   a - 428   d . When the amplitude of each output PIN  440   a - 440   d  (PIN number 3) is low (0 volts) current and charge flows out of the capacitor  428   a - 428   d  and to ground via the output PIN (PIN number 3). 
   In this embodiment, the supplemental intensity signal is generated by the additional flow of current passing through the upper LED  120  caused by the collective current drainage of the (4) timers  220   a - 220   d . The drainage of each timer  220   a - 220   d  constitutes a separate intensity transition signal. The current collectively drained by the (4) timers  220   a - 220   d  causes the additional current to flow through the upper LED  120 . The additional current flowing through the upper LED  120  collectively constitutes a supplemental intensity signal that passes through and is received by the upper LED  120 . The supplemental intensity signal is a superimposition of the drainage of each timer  220   a - 220   d.    
   When the amplitude of the output signal (PIN number 3)  440   a - 440   d  of each timer  220   a - 220   d  is high, the current that is being output through the output PIN  440   a - 440   d  is also being input (drained) into the timer  220   a - 220   d  via the discharge PIN (PIN number 7)  434   a - 434   d . The current being input (drained) into the timer  220   a - 220   d  is being drawn (sourced) from a circuit location  452  downstream of the output of the upper LED  120 . Drawing current from the circuit location  452  causes more current to pass through the upper LED  120  causing the upper LED  120  to emit light at a higher intensity in response to the more current passing through it. 
   When the amplitude of the output signal (PIN number 3)  440   a - 440   d  of each timer  221 - 220   d  is low, no current is being drawn by the timer  220   a - 220   d  from the circuit location  452 . Not drawing current from the circuit location  452  causes less current to pass through the upper LED  120  and causes the upper LED  120  to emit light at a lower intensity in response to the less current passing through it. 
   Optionally, resistors (not shown) can be added at one or more locations along the voltage drain conductor  450  to decrease the amount of current drained by the timers  220   a - 220   d . A resistor (not shown) disposed along the voltage drain conductor  450  at a location upstream of the drainage caused by one or more timers  220   a - 220   d  reduces the current drained by those timers. Such resistors can be disposed so that the intensity of the longer aspects of the flicker of the upper LED  120  can be reduced. 
   In other embodiments, other combinations of LEDs  110 ,  120  of different types, sizes and ratings and colors can be employed. For example, a 5 mm LED can be disposed below a 10 mm LED or a white LED can be disposed above a yellow LED, or vice versa. In some embodiments, rectangular LEDs  110 ,  120 , such as including one or more 2 mm by 5 mm LEDs are employed. 
   In some embodiments, the lower LED  110  and the upper LED  120 , of the same or different sizes, are encapsulated in a single translucent LED. In some embodiments, a first cluster of LEDs are disposed below a second cluster of LEDs. 
   In some embodiments, arrangements including other than (4) timers  220   a - 220   d  are utilized to create flame effects of differing complexity and character. For example, in some embodiments, (2) timers  220   a - 220   d  are employed while in other embodiments, (6) timers  220   a - 220   d  are employed. 
   Embodiments of the invention are not limited to those employing a 555 timer  220   a - 220   d . For example, in other embodiments, one or more intensity transition signals are generated by digital logic components including a crystal resonator and/or programmable microcontroller. 
   While the present invention has been explained with reference to the structure disclosed herein, it is not confined to the details set forth and this invention is intended to cover any modifications and changes as may come within the scope and spirit of the following claims.