CN1220076A - Series connected light string with filament shunt - Google Patents

Abstract

A series of series connected incandescent bulbs (12-21), wherein substantially all of the bulb filaments in the group each have a shunt element (31) which is inoperative during normal operation of the group and which is only shunted when the voltage across the shunt element rises above a predetermined value.

Description

The serial-connection light string of band filament shunting

One of general applications of lamp string is to decorate and show, especially at Christmas with other festive occasions, is used to dress a Christmas tree and other article.Perhaps be light fixture the most universal on the current market and have purposes widely, this light fixture comprises one or more groups lamp string, every group of lamp string has 50 miniature bulbs, and the rated operational voltage of each miniature bulb is generally 2.5V, and the filament of these bulbs connects into series circuit.Whole light fixture if desired surpasses 50 bulbs, and common way is the lamp string that is arranged to 50 bulbs of many groups, and the bulb of every group of lamp string is connected in series, and organizes the lamp polyphone more and is connected into parallel circuits.Because each bulb is connected in series in every group of lamp string, when a bulb can not throw light on for a certain reason, whole lamp string just can not be luminous, finds and replace that out of order bulb makes us puzzling very much and consuming time.Often before finding the bulb of inefficacy, have to check many bulbs.In fact, under many circumstances, this puzzlement and consuming time be too big so that people before reusing the lamp string of this inefficacy, have just abandoned these lamp strings, replace with new lamp string.When a plurality of bulbs can not throw light on owing to multiple reason simultaneously, it is complicated more that problem just becomes, and these reasons have: the bulb of one or several inefficacy, and one or several unsettled lamp socket connects, or one or several bulb comes off from its corresponding lamp socket, or the like.

Multiple device and equipment are arranged in the market, test each bulb of unloading down from lamp socket with electrical method.Test the equipment of Christmas tree bulb on the market in addition, the ac line voltage transducer is placed on practically the vicinity of concrete bulb to be measured.Yet this equipment is the electromagnetic field intensity checkout equipment, and when the concrete bulb of Christmas tree to be measured is positioned at this Christmas tree another or several bulb when contiguous, this equipment may always be pointed out " connection " situation.

In fact, bulbmaker also attempts to solve the detection problem of bad bulb, no matter what reason is when causing bulb to burn out, each burns out lamp envelope design and becomes its filament to form short circuit in the lamp string, thereby avoids burning out the situation that forms open circuit on the lamp socket of bulb.Yet, find that in practice this short circuit feature of bulb inside does not always form according to the mode of imagination, when a bulb burnt out, whole lamp string all extinguished.

At the patent application serial number with the same applicant of the application is 08/335,506, date of application is on November 7th, 1994, title is in " circuit tester of Christmas tree light fixture group ", disclosed a kind of novel hand-held and battery supply set, this equipment can the test lamp string in each bulb and do not need bulb is unloaded down from lamp socket, thereby find that make that whole series bulb extinguishes to burn out bulb easily.

Although above-mentioned the whole bag of tricks has been obtained some success, but also there are not which equipment and method can further solve the other problems that whole lamp string extinguishes, the reason that the lamp string extinguishes has: the lamp socket of inefficacy, bulb is installed inappropriate in lamp socket, the filament that wrecks in the bulb, or when bulb be unload maybe on hanging over Christmas tree from its lamp socket wittingly after since the carrying bulb only break away from from its lamp socket, especially be subjected to causing under wind or other weather conditions in outdoor mounted.

Burn out in order when causing one or several bulb to burn out, to protect all the other bulbs to exempt from owing to certain reason; patent 4,450, the 382 direct current bulb parallel connections that utilize Zener (Zener) diode to connect with each; these bulbs are used on truck and other vehicles, on Military Tractor.Wherein it is said, utilize single or multiple parallel diode not protect the mobile bulb that causes of rated current normally to lose efficacy, but protection forms the fault that the super-high-current surge causes because of bulb lost efficacy.Wherein do not mention any mechanism or technology, reach the stage that successfully to deal with problems with very simple and economical method by applicant.

Also proposed other the whole bag of tricks before this, and utilized all kinds in parallel with each light bulb filament along separate routes, the lamp string still continues illumination when a bulb burns out, and perhaps in contrast, provides open-circuit condition.Yet, known to applicant, once on market, occurred without any a kind of device.

Typical case's representative of these devices can be found in following patent.United States Patent (USP) RE34,717; 1,024,495; 2,072,337; 2,760,120; 3,639,805; 3,912,966; 4,450,382; 4,682,079; 4,727,449; 5,379,214 and 5,006,724, and British patent 12,398; Swiss Patent 427,021 and French Patent (FRP) 884,370.

In the above-mentioned prior art patent, at first sight come, Fleck ' 449, Harnden ' 966, and Switzerland ' 021 patent is the most promising in the prior art, utilize filament shunt circuit and/or all kinds device to indicate the bulb that lost efficacy in the lamp string, the scope of these devices is from the polycrystalline material to the powder and metal oxide varistor, or the like, can provide continuous electric current to flow through the lamp string, but be on the higher or lower level.Its reason is because such fact, appear at prior art each when the voltage drop value at two ends is with normal operation along separate routes incandescent lamp bulb both end voltage depreciation differ widely.Some of this prior art make the electric current of Series lamp string reduce along separate routes, because when a bulb is not worked, very high voltage drop appears at this two ends along separate routes, the idle reason of this bulb has: filament disconnects, bulb lost efficacy, lamp socket lost efficacy, or for no other reason than that bulb is installed inappropriately on lamp socket, or bulb takes off or comes off from its corresponding lamp socket fully.Yet some other branch apparatus causes reverse effect because of electric current strengthens.For example, when the voltage drop at lamp socket two ends reduced, high voltage was added in the lamp string on all remaining bulbs, and high voltage causes bigger electric current to pass through, and the life-span expectation value of all the other bulbs in the lamp string is reduced.And this high voltage also can cause all the other each bulb output light quantities increases in the lamp string, and this result is undesirable in some cases.Yet when the voltage drop at socket two ends increased, low voltage was added on all the other bulbs that all are connected in series in the lamp string, and low voltage causes less current to be passed through, and has correspondingly reduced the output light quantity of all the other each bulbs in the lamp string.This undesirable effect appears in the method for whole prior aries, comprise that those at first sight come the most promising technology, especially in Fleck ' 449 patents, suggestion uses diode to connect with bidirectional switch, or in above-mentioned Harnden ' 966 patents, metal oxide varistor is used in suggestion, or in Switzerland ' 021 patent, the rectifier that oppositely connects is used in suggestion.

For example, in the device of above-mentioned Fleck ' 449 patents suggestion, use ten based on halogen bulb in the series circuit, each bulb has 12V minimum rated operating voltage.The existence of halogen gas just can allow big electric current to flow through filament in the bubble, consequently obtains bright light in very undersized bulb.Usually, ten 12V Halogen lamp LEDs connect into a Series lamp string, and when any one bulb lost efficacy, whole lamp string extinguished, but do not indicate which bulb do not lose efficacy.In order to improve this undesirable effect, Fleck proposes to add the shunt circuit of being connected with diode by silicon bi-directional voltage trigger switch at each based on halogen bulb two ends, diode pair exchanges (promptly, " A.C. ") voltage carries out rectification, thereby make electric current only in the time of half, flow through bidirectional switch, promptly in each half period electric current is arranged at A.C. voltage.Described in the Fleck patent, when a bulb burns out, just " minimizings " light output of all the other bulbs, because diode almost makes effective voltage reduce half, this is to stop electric current to pass through in one direction owing to diode, only allows the rightabout stream that powers on to pass through.This light output that significantly reduces obviously makes the bulb that it should be noted that inefficacy and avoids adding higher voltage, and higher voltage can make all the other light bulb filament losts of life.Yet, in actual use, observed brightness and sharply descended, that is, when a bulb extinguishes, drop to about 15lux from about 314lux.And according to the patent application person, the process that above-mentioned replacement burns out bulb relates to interruption institute making alive, in order that make the switch disconnection and recover operate as normal later at the replacement bulb.(see the 2nd hurdle, 19-22 is capable) in addition, this device does not allow several bulbs to extinguish simultaneously, the required special-effect that some is additional, for example " flicker " or the like obviously is impossible.

In the device of Harrnden ' 966 patents suggestion, Harnden proposes to utilize the polycrystalline metal oxide varistor as shunting device, although such well known fact basis is arranged, metal oxide varistor is not to be designed to allow continuous current flow through wherein.Therefore, this rheostat only is a kind of purpose what is called " direct action " device that is used to protect, i.e. transient voltage suppresser, and its effect is that absorbing high-frequency is the quick voltage spiking, thereby avoids this voltage spike to damage relevant circuit.This rheostat is designed to as the spiking absorber, rather than is designed to as voltage regulator or steady-state current dissipation circuit.Though metal oxide varistor can appear at some occasion that is similar to back-to-back Zener diode, these two kinds of devices are non-interchangeable, differ widely according to its special purpose function.In fact, Harnden ' 966 assignees once were General Electric Co. Limited (General Electric Corporation) in the past, obviously be Harris semiconductor company now, point out in its application explanation 9311: " metal oxide varistor is very superior for dissipation instantaneous voltage spiking, but can not dissipate continuous low-level of power." in fact, the assignee points out that also their metal oxide varistor can not be used as voltage regulator, because its function is as the nonlinear impedance device.Unique resemblance of metal oxide varistor and back-to-back Zener diode is, the two all is a bilateral device, in addition, and no common ground.Point out also that in the Harnden patent rated value that rheostat preferably has is 125% of a bulb rated value, such rated value can make under all the other bulb sides are on the series circuit " stress that reduces ".Correct explanation is that this what is called " stress that reduces " causes all the other bulb illumination to reduce.For example, be operated in 50 lamp bulb strings under the A.C.120V, the average voltage on each bulb be 2.4V rms (" root mean square ") promptly, crest voltage 3.39V.Because rheostat is to the response of peak electricity pressure energy, rheostat 125% rated value is exactly 4.24V, is equivalent to 3.0Vrms.2.4V with the difference of 3.0V be vital for causing single bulb to lose efficacy, especially at other bulbs in succession under the situation of failure combination, for example, hang over one group of 50 bulb string on the outdoor bushes, stand strong wind and other motion.Therefore, this device is not suitable for applicant fully and wants the purpose that reaches.

In Switzerland ' 021 patent, Dyre discloses a bidirectional shunt device, and it has the breakdown voltage rating value, and when surpassing this value, the resistance value of this device drops to 1 Ohm or littler.Even when only a bulb can not be worked owing to a variety of causes above-mentioned, this low resistance will make the voltage that is added on all the other bulbs increase a lot of.Therefore, when a plurality of bulbs can not be worked, be added on remaining bulb with regard to having higher voltage, from and increase the illumination of these bulbs widely, so, shorten the life expectancy value of these bulbs widely.

With above contrast, utilize the shunt type of applicant suggestion, when all bulb can not be worked owing to some or all reasons above-mentioned basically in 50 bulb strings, the illumination intensity of all the other bulbs only reduced seldom, and this situation is that above-mentioned arbitrary shunt can not realize.In addition, the fact that acquires a special sense is, Switzerland ' 21 patents for being familiar with this professional people over and done with 30 years, Harnden ' 966 patents are also over and done with twenties years, Fleck ' 449 patents were pass by again more than 8 years, but, also be combined in so far and form commodity on the market without any a patent or its.In fact, present small-sized Christmas tree bulb only relies on the bulb of particular design, and this bulb will short circuit in the time can not working, and obviously, this scheme can not be always effective, and especially unload the back or damaged when carrying from its lamp socket when bulb, or the like.Some other people's extreme idea is, allows bulb to come off from its lamp socket anything but, and this idea comprises: the respective flanges engagement that utilizes the lock slots that forms on the lamp socket inside edge and light bulb base unit bottom to form.Though this special locking means is highly effective for preventing that bulb from coming off from its lamp socket, but, common user to replace inefficacy bulb and without recourse to mechanical clamp, if not be impossible sometimes, but also be extremely difficult, in fact this clamp can damage light bulb base unit or lamp socket.

According to the present invention, a kind of filament shunt circuit of novelty is provided, be used to connect a string incandescent lamp bulb that is connected in series, this shunt circuit is with very simple, novel and economic method has overcome the problem of existing apparatus existence before this fully, the design of existing apparatus mainly is when one or several bulb can not be worked in the line, only how much keep some electric currents and flow through whole series bulb, the inoperable reason of bulb has: filament has broken, the bulb of one or several inefficacy, the lamp socket of one or several inefficacy, perhaps, perhaps intactly take off or come off from its corresponding lamp socket for no other reason than that one or several bulb suitably is not fixed on its corresponding lamp socket.

According to the present invention, the incandescent lamp bulb of a string series connection is provided, each bulb has the silicon type shunting device of cross-over connection at its two ends, this device has a predetermined voltage switch value, this voltage switch value is greater than the normal voltage that is added on the described bulb, have only when the crest voltage that is connected across the shunting device two ends surpasses its described predetermined voltage switch value, this shunting device is conducting fully just, this situation in the lamp string bulb or several bulb or all bulb since underlying cause take place can not work the time: filament has broken, the bulb that lost efficacy or damaged, the lamp socket that lost efficacy, perhaps, perhaps intactly take off or come off from its corresponding lamp socket for no other reason than that bulb suitably is not fixed on its corresponding lamp socket; Even when a great deal of bulb can not be worked simultaneously owing to the combination in any of above-mentioned a variety of causes in all bulbs in the lamp string, the sort circuit arrangement can make rated current flow through all remaining bulbs in the lamp string constantly, and the light that any bulb is exported in those remaining work bulbs in the lamp string still has roughly constant illumination.

So, main purpose of the present invention is, a simple and cheap silicon type filament shunting or a bypass is provided for a plurality of each bulb that is connected in series, described filament shunting has a predetermined voltage switch value, this voltage switch value is slightly larger than described bulb rated voltage, when being added in along separate routes the crest voltage at two ends and surpassing its described predetermined voltage switch value, this shunt is with regard to conducting, this situation in above-mentioned a variety of causes arbitrary take place when existing, this shunt can make and continue to flow through each remaining bulb in the lamp string with unbroken rated current, and from the light of wherein output roughly constant illumination is arranged.

Another object of the present invention is, a kind of novelty and the improved bulb string that is connected in series are provided, has the above-mentioned required feature of mentioning, and has very simple and economical structure, relatively cheap when making in batches, thereby the overall price that makes final products keeps minimum on market, and without any need for the bulb of particular design, and nearly all bulb string requires to form short circuit when bulb burns out on current market.

Another object of the present invention is, a kind of bulb string that is connected in series with above-mentioned all features is provided, wherein the light that penetrates from each bulb can randomly and independently and continuously occur along whole series bulb, disappear and reproduction, thereby create a kind of very noticeable, novel and uncommon flicker effect.

Fig. 1 is the novel lamp string road schematic diagram according to the first embodiment of the invention structure;

Fig. 2 is the novel lamp string road schematic diagram according to the second embodiment of the invention structure;

Fig. 3 is the novel lamp string road schematic diagram according to the third embodiment of the invention structure; With

Fig. 4 is the novel lamp string road schematic diagram according to the four embodiment of the invention structure.

With reference to the schematic diagram among Fig. 1, comprise input 10 and 11 according to a first embodiment of the invention, these two inputs are suitable for being connected to average family and shop 110/120V AC power appropriate device commonly used.Input 10 generally is fixedly connected to first end of first lamp socket, inserts first bulb 12 in first lamp socket effectively.The abutting end of first lamp socket is connected to the abutting end of second lamp socket, insert second bulb 13 in second lamp socket effectively, or the like, each bulb connects into series circuit between input 10 and 11 effectively in whole lamp string (no matter be 10 bulbs altogether that schematic diagram draws, still 50 bulbs altogether) generally speaking.Effectively be connected in parallel with first lamp socket two electric terminals, promptly be connected with 12 two electric terminals of first bulb, be first voltage-sensitive switch 22, this switch draws with sign format, and its effective function is the following conduct that will the describe first voltage adjuster spare.Similarly, effectively be connected in parallel with second lamp socket two electric terminals, promptly be connected with 13 two electric terminals of second bulb, it is second voltage-sensitive switch 23, similarly its effective efficiency is as voltage adjuster spare, or the like, up to remaining each lamp socket, be each bulb 14 to 21 of all the other series connection, a corresponding voltage-sensitive switch 24 to 31 that effectively is connected in parallel with its two ends is arranged.

From practical application, preferably, all voltage response switch 22 to 31 all has identical structure, has such characteristic ideally, and when conducting, promptly under " connection " or " closure " state, its resistance value equals corresponding light bulb filament impedance; When non-conduction, promptly under " disconnection " or " obstruction " state, its resistance hole value equals infinitely great.

We find, when two know be referred to as the back-to-back connection of semiconductor device of " Zener " diode the time (, differential concatenation connects), these two semiconductor device have the desirable characteristics as fabulous voltage response switch, its function is according to voltage adjuster spare of the present invention basically, particularly on market, can buy with low relatively price owing to this back-to-back Zener diode, especially true when buying relatively in enormous quantities.Working method embodiment illustrated in fig. 1 is as described below:

Suppose that this lamp string is the typical case's 50 lamp strings that contain 50 bulbs that are connected in series, the rated voltage of each bulb is 2.4V, and effective rated voltage of whole lamp string determines that by 2.4V * 50 its product equals 120V.Two ends at each bulb connect the Zener diode (these two Zener diodes can all be made in the inside of lamp socket itself) that two back-to-back differential concatenations connect, the rated voltage of each Zener diode is 3.3V, when the 200mA electric current passed through, the voltage of each bulb side can not surpass about 4.5V.When in the lamp string during illumination of bulb (" connection "), the voltage of that bulb side is about 2.4V (or about 3.4V, peak value), and certain, this voltage depends on added line magnitude of voltage of that particular moment.When two Zener diodes are connected across each bulb side in back-to-back mode, and the rated voltage of each Zener diode is 3.3V, does not then have electric current to pass through any Zener diode basically, and whole basically electric currents are by each bulb that is connected in series.When a bulb when its corresponding lamp socket takes off, or when burning out, or the like, and bulb inside does not have short circuit mechanism, then the voltage at those certain bulb two ends begins to rise, and rises towards institute's ledger line magnitude of voltage size.Yet the Zener diode of two back-to-back connections of 3.3V is connected across on that certain bulb, and before two Zener diodes began conducting, the voltage that is connected across above the bulb can only rise to about 4.5V.About 1.1V peak value fell in that lamp socket both end voltage when this only surpassed corresponding bulb conducting).All the other bulbs in this lamp string almost are not subjected to the influence of extra 1.1V (peak value) voltage drop in the Zener circuit.Each remaining bulb side voltage has only reduced about 23mV (peak value) in this lamp string.Therefore, there is not electric current before reaching desirable value, to pass through diversion mechanism basically.

Extraordinary and desirable characteristics that the foregoing description is better than prior art lamp string be, the lamp string continues to keep illuminating, there is not one or several bulb to burn out in the spot string actually, or from corresponding lamp socket, comes off, or loosening or insert crookedly on corresponding lamp socket.Any variation has not taken place in one or several bulb in the spot string, and the lamp string keeps illuminating.Therefore, back-to-back connection Zener diode guarantees that electric current continues to pass through in the series conductor circuit, irrelevant with the bulb situation that the shunt two ends are specific.Yet, insert if desired in " flash of light " bulb to a lamp socket of a standard, as normal condition, when flashbulb changes state at every turn, whole lamp string will be lighted and extinguish, be necessary to save a zener diode, preferably, then flashbulb be inserted in that specific lamp socket near that lamp socket of A.C. plug at lamp socket two ends.After this, the lamp string will glisten according to normal mode.

The rated voltage that will be appreciated that and understand above-mentioned each Zener diode is 3.3V, this means that when certain Zener diode both end voltage at first reached 3.3V, this Zener diode was just oppositely beginning conducting.In contrast, when Zener diode during at forward conduction, the voltage drop at these Zener diode two ends is about 0.7V.Therefore, when connecting into back-to-back structure on two such Zener diode circuits, effective breakdown voltage rating of this zener diode (to call " effectively rated voltage " in the following text) is about 4.0V (promptly, 3.3V+0.7V), because a Zener diode forward conduction of this centering, and another Zener diode reverse-conducting of this centering.Therefore, this zener diode is a polar-symmetric,, identical polarity is arranged on the both direction that is.At about 200mA electric current, before promptly the average current in 50 bulb strings flow through wherein, along with bigger electric current is right by this back-to-back Zener diode, this 4.0V magnitude of voltage can increase, after this, the voltage drop at the back-to-back Zener diode two ends of two rated voltage 3.3V reaches 4.4V.This back-to-back Zener diode can be the DZ89 series " two Zener diode " that the ITT semiconductor company of buying on the market produces.Various load voltage values are arranged, and rated value is often represented with crest voltage, or is expressed as exchanging rated value sometimes.

Because " electric current puncture " condition of knowing, each back-to-back Zener diode is right, and promptly two Zener diodes can be avoided self burning out, this is the electric current restriction effect because of all the other bulbs that are connected in series in the lamp string, and size of current is wherein flow through in the total resistance value decision in the lamp string.For example, if after all bulb takes off from the lamp string, then 120V (A.C.) or 170V (peak value) supply voltage are added in 50 two ends along separate routes.Since each back-to-back Zener diode along separate routes effectively rated value be 4.0V (peak value), and each along separate routes the voltage at two ends have only 3.4V (peak value), very little or do not have electric current in the lamp string, to flow through.

Another kind device preferably is a two-way silicon trigger switch (STS), HS series, and this device can be buied from the subordinate's of Siebe company Teccor electronics corporation now, but present price is slightly more expensive than back-to-back Zener type switch.The same with back-to-back Zener type switch, so-called " STS, HS series " type switch has low conducting voltage, is mounted to economic DO-35 assembly, has the glassivation planar junction to improve reliability.When institute's making alive, no matter arbitrary polarity, when surpassing conducting voltage, " HS " device just is transformed into conduction mode from blocking model, and this device is bilateral device still not, and, the same with back-to-back Zener diode, also be very symmetrical for alternating current is used.Draw as schematic diagram among Fig. 2, shown in each two-way silicon trigger switch 22 ' to 31 ' respectively in parallel with a corresponding bulb in the bulb 12 to 21 that is connected in series, that draws in its mode and the prior figures 1 is the same.

The working method of silicon trigger switch embodiment shown in Figure 2 is identical with back-to-back Zener diode embodiment shown in Figure 1 basically.Yet in the STS embodiment that utilizes Teccor type HS-10 silicon trigger switch as shunt, specified trigger voltage is about 10V, and when the STS conducting, substantially the same about 2.4V voltage drop appears on each lamp socket of 50 miniature lamp strings once more.When STS device and each lamp socket along separate routes the time, before corresponding bulb waters bad or takes off from its lamp socket, there is not electric current in the STS device.After this, reaching before about 10V, voltage begins to rise, and at this moment, the STS device arrives " conducting " state with " shutoffs " state exchange.Under " conducting " state, the voltage at STS device two ends is about 2.4V in 50 lamp bulb strings of 200mA, and most of bulb is work in this moment 50 lamp bulb strings, and this magnitude of voltage is identical when bulb is worked in its lamp socket accordingly.Therefore, whether one or more remaining bulbs do not work in the spot string, and the voltage drop of each remaining bulb side remains unchanged basically.Another advantage of STS embodiment is in order to obtain required " flicker " or " flicker flash of light " effect, not need to take off along separate routes from a lamp socket.Yet, in order to obtain " flash of light " effect of standard, the flash of light of " lighting " and " extinguishing " appears in the lamp string, just need take off STS along separate routes from a lamp socket, preferably take off that shunt of the most close A.C. socket.

For example, because STS has threshold value clearly along separate routes, non-flashbulb is placed in first lamp socket (not having STS along separate routes), flashbulb is placed in all the other all lamp sockets, this lamp string will glimmer and glisten.When at least 12 to 13 bulbs were in " extinguishing " state simultaneously, the flash of light in the flash lamp string just can take place.This is because when STS device both end voltage reaches about 10V, just is transformed into conducting state.So, on the 120V power circuit, before the lamp string extinguishes, to have 12 to 13 bulbs to be in " extinguishing " state.When photoflash lamp returned to its normally state, the lamp string was lighted again and is glimmered, and was in " extinguishing " state more simultaneously up to 12 to 13 bulbs.The periodicity of this flash of light " disconnection " and " connection " is the function of flashbulb.If flashbulb was lighted in the most of the time, have only the very short time cycle to be in " extinguishing " state, making 12 to 13 bulbs be in " extinguishing " state simultaneously is once in a while, and will cause glistens the short time cycle, and flicker has the long time cycle.

A kind of circuit arrangement of drawing embodiment illustrated in fig. 3, except working voltage source was the pulsation full-wave rectified voltage of common 60 all twices, the operation of this circuit is identical with two embodiment in front basically.As shown in Figure 3, STS device 22 " to 31 " constitutes along separate routes with bulb 12 to 21 two ends respectively, and these bulbs are the miniature lamp string of 50 bulbs preferably.Preferably, carry out full-wave rectifier 9 in the power line socket, between two line end 6 and 7, be connected one 3.9 μ F capacitor.This special circuit arrangement has been arranged, and the bulb in 50 bulb groups only can glimmer, and can not aforesaid flicker flash of light.As noted, rectifier 9 and capacitor 8 can be installed in the A.C. plug, perhaps are made in the adaper plug separately, and power-line plug inserts wherein.This just can be added to the direct current (that is, " D.C. ") of pulsation and part filtering on the lamp string.The STS device is transformed into " disconnection " when needing direct current to be in " extinguishing " state to avoid flashbulb, does not make STS device " disconnection " because direct voltage can not reach zero volt.Under A.C. ruuning situation, be triggered " disconnection " and " conducting " per second 120 times of STS device.Under STS device " disconnection " state, need 10V voltage to make it return to conducting approximately.The reason that the bulb number that Here it is uses working volts alternating current to glimmer is restricted.Yet, use direct-current working volts, before relevant flashbulb illuminated, the STS device kept conducting always.So the bulb number is unrestricted in this lamp string.Though use direct voltage as operating voltage, the bulb number that can glimmer in the circuit is unrestricted, should be mentioned that the consideration of another matching condition.If only use a bridge rectifier, the pulsating voltage of output does not add filtering, and then the effect on the lamp string is as using alternating voltage as operating voltage.This is because STS device meeting " conducting " and " disconnection " per second 120 times, the i.e. a-c cycle of twice.A rectifier is installed at two ends in bridge rectifier output, just has improvement on performance.Yet if capacitor 8 is too little, intensity of light will flicker, and especially mixes some flashbulbs in the normal bulb in the lamp string.In addition, the electric current in the circuit is too little.If the capacitor that uses is too big, and is just excessive by the electric current of bulb, can shorten the life-span of bulb.So desirable capacitance is to make that the electric current by bulb is common 200m A in common 50 miniature lamp lamp strings.Under this level, the mobile of electric current is stable, and the lamp string is working properly.In 50 miniature lamp lamp strings, more suitable capacitance is about 3.3 to 4.7 μ F.If now one or several flashbulb is inserted in the lamp string, each flashbulb still continues " to light " and " extinguishing " with itself independent frequency.When putting into more bulb, just need bigger capacitance.

In another embodiment shown in Figure 4, a kind of circuit arrangement of having drawn, except the single Zener diode of each lamp socket cross-over connection as the shunt, the operation of this circuit is identical with previously described several embodiment basically, preferably, half of Zener diode sum is towards a predetermined direction job, as drawing on the bulb 12 to 16 in the circuit, and second half remaining Zener diode is worked in the opposite direction, as drawing on the bulb 17 to 21.

Just for convenience of explanation, supposing that circuit shown in Fig. 4 (as Fig. 1 to Fig. 3) comprises adds up to 50 incandescent lamp bulbs that are connected in series, be convenient to illustrate 12 to 210 bulbs of bulb that only drawn, input service voltage is about interchange 120Vrms, is equivalent to exchange approximately the 170V crest voltage.In the case, if all bulb has identical rated value, normal conditions also are like this, and the average rms voltage that then is assigned on each bulb is about 2.4V, or crest voltage is about 3.4V.At 6.2V Zener diode of each bulb side cross-over connection as along separate routes, represent with (22) to (26) along separate routes for preceding 25, their polarity separately connects by a direction, as shown in the figure, represent with (27) to (31) that along separate routes their polarity is separately pressed opposite direction and connected for remaining 25, as shown in the figure, the voltage drop of every bulb side is about 120V divided by 50, that is, be about 2.4Vrms or be about crest voltage 3.4V.This is because in the half the time of input voltage ac cycle, preceding 25 shunt forward bias, and each about 0.7 to 0.8V crest voltage occurs in two ends along separate routes, and the peak electricity pressure drop at preceding 25 shunt two ends is about 17.5 altogether to 20V.The crest voltage that each bulb of placing on these lamp sockets was assigned in first half period of operating voltage is about 0.7 to 0.8V, and brightness output is temporary transient to descend thereby make.Yet the AC power crest voltage is about 150 to 152.5V remaining among 170V crest voltages and is added in 25 other shunt.This just causes, and about 6.0 to 6.1V crest voltages are added on each bulb with reverse bias in the time of described first half period of AC supply voltage, thereby make temporary transient rising of bulb brightness output of placing on these lamp sockets.In AC supply voltage in the time of next half period, bias condition is separately all put upside down, promptly, those bulbs that are assigned to about 0.7 to the 0.8V crest voltage of forward bias in first half period just are assigned to about 6.0 to the 6.1V crest voltages of reverse bias in second half period, for all the other bulbs in the lamp string, vice versa.So the average voltage drop in complete positive negative cycle of alternating current on each bulb is about crest voltage 3.4V, or peak one peak voltage 6.8V, this voltage is corresponding to the rated value of used concrete bulb in the Series lamp string.This is because though crest voltage is identical in both cases, effective voltage is inequality.Under normal circumstances, waveform is sinusoidal, and under Zener diode shunt situation, ac power waveform is a half-sine wave and half square wave.Sinusoidal wave half is about 6.2V (peak value), and remaining half is square wave, is about 0.7V (peak value).This result is the poor of rms value, rather than peak value is poor.So crest voltage is substantially the same, and rms voltage is not substantially the same.Unless reduce the input AC operating voltage, perhaps add more bulb in the Series lamp string, more than this operation can cause bulb life to shorten.Theoretically, in order to work under the about 120Vrms of common alternating voltage, this voltage is equivalent to the 170V crest voltage, should add about 1/3rd bulbs in the line, and making in the circuit all, bulbs throw light under the normal brightness level.

Be in operation, because a variety of causes above-mentioned, except internal short-circuit, when only having a bulb not work, voltage drop crest voltage under the forward situation in that corresponding Zener diode shunt is about 0.7 to 0.8V, crest voltage is about 6.2V under inversion condition, and hypothesis selects for use the 6.2V Zener diode as shunt here.Therefore, in complete cycle of adding work voltage, that certain bulb lamp socket both end voltage absolute value is increased to the about 6.2V of crest voltage from about 0V in order, drop to crest voltage about 0.7 to 0.8V, return about 0V, thereby the average about 2.44V of rms voltage, the rated value with bulb is identical basically.In fact, in laboratory tests, we find, can take off 49 bulbs from 50 bulb strings, allow unique bulb that stays continue illumination, estimate that its brightness descends and has only about 50%.

Not in the lamp string that is connected in series of 50 bulbs, only need to select the Zener diode of suitable rated value as shunt, then the half Zener diode is connected along direction of circuit, remaining half connects in opposite direction, needn't consider which shunt or which certain specific direction of branch curb connect, as long as above-mentioned overall relation is set up.For example, consider, may require alternately to change polarity along separate routes from making viewpoint.In addition, for odd number bulb situation in the circuit, for example, 35 bulbs can be divided into two groups to polarity, and one group is 17, and another group is 18.

Effectively utilize " triggering " type power division mode of this novelty, just can adopt single Zener diode as unique switch element in actual use, rather than two back-to-back Zener diodes among Fig. 1, silicon bi-directional switch in neither Fig. 2, can also further reduce the manufacturing cost of whole lamp string, consider to be competitiveness extremely from the cost viewpoint in current market, attempt from the beginning only adopts single Zener diode so that be of practical significance on market in people such as Sander ' 079 patent.Consider that from accurate manufacturing cost viewpoint according to estimates, under the batch process situation, the cost of single Zener diode is about 2.0 cents, the single manufacturing cost of back-to-back Zener diode is about 2.3 cents, and the cost of HS-10 silicon bi-directional switch is about 5.0 cents.

Generally speaking, adopt " back-to-back " Zener diode or " going fifty-fifty " single Zener diode as filament shunting, when one of above-mentioned a variety of causes causes a bulb not work, the voltage that is added in all the other each bulb sides in the Series lamp string just descends slightly, and if adopt silicon bi-directional switch as filament shunting, then when above-mentioned arbitrary reason causes a bulb not work, be added in that the voltage of all the other each bulb sides rises slightly in the Series lamp string.Situation comes to this, and before whole series bulb will burn out at once, all basically bulbs can not worked.

The voltage-sensitive switch of having showed various other types in the Radio Shack semiconductor reference manual, adopt the voltage-sensitive switch that has above-mentioned similar characteristics among the Archer catalogue #276-405 (1992) can obtain identical or essentially identical effect, actual selection is determined by the price of device and the occasion of use.

Described and illustrated my inventive principle in a preferred embodiment, so, intraparenchymatous all various variations and changes of scope and spirit in following claims in appended claims, covered.For example, be familiar with these professional people and obviously know, can adopt other similar devices and obtain identical effect,, can adopt the Zener diode of different rated values for not being both bulb.

Claims (12)

1. A light string of incandescent light bulbs connected in series for Christmas trees etc. These light bulbs can be powered by an AC working voltage source, the improvement is that substantially all of the light bulbs in the light string have electrically symmetrical external shunt circuits at both ends of their filaments respectively connection, this shunt circuit consists of a bi-directional silicon type voltage responsive switching device which effectively functions as a voltage regulator and is inactive during normal operation of the string; only if the voltage applied across it is at least equal to its own effective rated voltage It will only work when the rated voltage of the bulb is exceeded. This situation is caused by some of the following faults: bulb filament broken, failed bulb, failed bulb holder, bulb not properly fixed in its corresponding lamp socket, the bulb is removed or falls off from its corresponding socket, etc. This device also provides a continuous flow of current substantially at rated current through all remaining bulbs in the string, even when multiple bulbs are out of service, the remaining bulbs still have a substantially constant illuminance and approximately The rated current flows continuously. 2. 2. The apparatus of claim 1, wherein said voltage responsive switching means comprises back-to-back Zener diodes as primary functional elements. 3. The apparatus according to claim 1, wherein substantially all of said bulbs are flasher type bulbs. 4. 2. The apparatus of claim 1, wherein all light bulbs continue to illuminate even when substantially all light bulbs in the same string are inoperative. 5. A string of incandescent bulbs connected in series with an operating voltage source, the improvement being that substantially all of the bulb filaments in the string have their own external and bidirectional electrically symmetrical silicon-type shunt circuits including voltage responsive switching means, This device is inoperative during normal operation of a string of lights; only when the voltage across it increases due to filament failure of its corresponding bulb and this voltage is at least equal to the effective rated voltage, the minimum number of bulbs in said string being determined by the specified The voltage drop characteristic when the switch device is turned on is selected to ensure that the voltage drop at both ends of the corresponding bulb filament remains basically unchanged when the filament of the corresponding bulb fails, and the continuous current passes through the remaining bulbs, even when multiple bulbs are switched from After falling off on its corresponding lamp holder, also basically maintain its constant illuminance. 6. 5. The apparatus according to claim 5, wherein said voltage responsive switching means comprises a bi-directional silicon trigger switch as a primary functional element. 7. The apparatus according to claim 5, wherein said operating voltage source is a unidirectional voltage source. 8. 5. Apparatus according to claim 5, wherein all light bulbs continue to illuminate even if one or more other bulbs fail. 9. The apparatus according to claim 5, wherein substantially all of said bulbs are flasher type bulbs. 10. A novel and improved filament shunt light string comprising a combination of the following: A plurality of electric bulb holders interconnected in a series circuit arrangement, adapted to be powered by an electrical source connectable to an input thereof, each of said lampholders being adapted to insert an electric bulb therein whenever an alternating voltage is applied to said input , these bulbs can illuminate; a bi-directional, electrically symmetrical and silicon-type voltage responsive switching device connected in parallel across each of said lampholders; and means for connecting said input to a source of alternating voltage, whereby all illuminable bulbs in said string of lights continuously receive substantially the rated voltage therethrough, even if a substantial number of bulbs in the string fail to light for whatever reason A bulb that can illuminate continues to illuminate when it is removed from its corresponding lamp holder or when it falls off. 11. An apparatus for stringing incandescent bulbs connected in series using a voltage source, the improvement being that substantially all of the filaments of the bulbs in the string apparatus each have a corresponding external shunt circuit consisting of a silicon type voltage responsive switching device, This device is inactive during normal operation of the light string, and becomes active when the voltage across it rises so much due to the failure of its corresponding bulb that when active, the impedance of the switching device transitions to closely match the impedance of its corresponding bulb. When one or several other bulbs in the light string fail to work, the voltage drop across each illuminated bulb is substantially constant, and substantially the rated current continuously flows through these bulbs with a substantially constant brightness. 12. The light string of claim 10, wherein said voltage responsive switching means comprises Zener diodes, substantially half of the Zener diodes are electrically connected in one direction and the remaining half are electrically connected in the opposite direction.

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