Abstract:
A shunting mechanism is provided within a socket of a light string system having a resistive element that substantially mirrors the resistive characteristic of the bulb inserted in the socket. The shunting mechanism is disabled when the bulb is inserted into the light string socket. When the bulb is removed from the light string socket, the shunting mechanism bridges the internal socket leads so as to maintain current flow and power delivery at levels similar to those provided when the bulb is present. In one embodiment, the resistive element is a resistive coating on the shunting mechanism or a resistive node on the shunting mechanism. In other embodiments, the resistive element is applied to the socket&#39;s internal leads. In yet other embodiments, the resistive element consists of sophisticated electronic circuitry specifically designed to mirror the resistive characteristics of the bulb assembly.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to and the benefit of U.S. Provisional Patent Application No. 61/852,080 filed Mar. 15, 2013 and titled “APPARATUS AND METHOD FOR PROVIDING A RESISTIVE SHUNT WITHIN A LIGHT STRING” the contents of which are incorporated by reference herein in their entirety. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention is for a system and method for providing a resistive shunt that provides for connecting two terminals within a light socket of a light string when the bulb is removed. Essentially, a resistive element is included as part of or comprises the socket bridge itself such that when the light bulb is removed, the electrically resistive element is provided in series with the bridge so as to present the same resistance between the external socket leads as that provided by the bulb when it is inserted into the socket and operational. In this manner, the overall resistance characteristics of the light string are not changed upon the removal of one or more bulbs in the light string and power/current demand increases are avoided within the light string system upon bulb removal. 
     2. Description of the Prior Art 
     Holiday light strings are an omnipresent facet of many holiday decoration displays. Safety is one of the primary concerns in designing these light string systems. In particular, the removal of bulbs from the sockets within which the bulb typically resides presents several practical operational problems as well as safety concerns. Numerous bridging technologies exist that provide for a closed circuit condition within the socket when bulbs are removed such that the remaining bulbs in the light string remain lit. For Example, U.S. Pat. No. 7,591,658 issued on Sep. 22, 2009 to Chen (hereinafter “Chen”) provides one such shunting system in which one of the legs of an electrically conductive torsion spring is moved into a bridging position connecting the internal socket leads when the bulb is removed from the socket. One problem with this arrangement, however, is that the torsion spring is typically made of copper or another low resistance conductor. Thus, the removal of the bulb, including its associated filament resistance, causes the current drawn by the light string to increase upon bulb removal. If numerous bulbs are removed from a string, this problem increases, potentially to the point of dangerous operation. Commercial light string systems are typically rated for a maximum current draw or power consumption, and any increases up to or over those limits may be considered a safety hazard. 
     Underwriters Laboratories (UL) is a safety consulting and certification company that provides safety-related certification, validation, testing and inspection services. The organization advises and trains manufacturers of commercial manufacturers on various safety-related topics. UL certification is often a requirement for commercially distributed electrical systems to be offered to the public. Many retail outlets that offer holiday light string systems, for example, require that the light strings and components offered by their manufacturers pass UL certification as a condition of being offered for sale in their retail establishments. Numerous other worldwide certification organizations exist that provide similar functions and services. 
     Maximum light string current draw or power consumption is one of the most recent safety requirements to be formulated by electrical safety, standards-setting bodies. UL 588, for example, covers seasonal and holiday decorative products, specifically “factory-assembled seasonal lighting strings with push-in, midget-screw, or miniature-screw lamp holders connected in series for across-the-line use or with candelabra- or intermediate-screw lamp holders connected in parallel for direct-connection use . . . . [and] which are portable and not permanently connected to a power source.” To achieve UL certification under this specification section, a shorting test of light sockets shunts is conducted wherein bulbs are removed one at a time until many bulbs are removed from a single string. To achieve UL certification under this standard, the current of the light string shall not increase beyond a certain percentage, typically 10%. 
     Thus the need exists in the industry in which a shunting mechanism is provided, within a bulb socket and external to the bulb itself, such that the resistive characteristics of the shunt mirror those of the removed bulb. This may be as simple as matching a resistance of the two. In more complicated systems, the bulb circuitry can be mirrored within the shunting mechanism itself. In any case, any number of bulbs may be removed from the light string containing such a system without appreciable increased in current or power dissipation, thereby achieving the goals of the above-mentioned standards organizations and creating a safer light string system. 
     BRIEF SUMMARY OF THE INVENTION 
     In one particularly preferred embodiment, a light string socket is provided having at least two leads through which electrical power is delivered to the socket, the socket configured to receive a bulb assembly having two bulb leads, the two bulb leads being in electrical contact with the at least two socket leads such that when the bulb assembly is seated in the socket the electrical power flows through the bulb, the socket including: a shunt within the socket, the shunt bridging the at least two electrical leads within the socket when the bulb is not seated in the socket, and a resistive element is coupled to either the shunt or the leads such that the electrical power flows through the resistive element and the shunt when the bulb is not seated in the socket, the resistive element being matched to a resistive characteristic of the bulb so that the electrical power provided to the socket is substantially similar whether the electrical power is consumed by the bulb or the resistive element. 
     In other aspects of this embodiment, the resistive element is one of: a carbon coating deposited on the shunt, a resistor, a microelectronic circuit module, a resistive bead, or a spring; or the shunt is mechanically coupled to one of the at least two leads; or the resistive characteristic is an electrical resistance of the bulb and a resistance of the resistive element is matched to the electrical resistance of the bulb. 
     In another particularly preferred embodiment of the invention, a light string socket is provided having at least two leads through which electrical power is delivered to the socket, the socket configured to receive a bulb assembly having two bulb leads, the two bulb leads being in electrical contact with the at least two socket leads such that when the bulb assembly is seated in the socket the electrical power flows through the bulb, the socket including: a shunt within the socket, the shunt bridging the at least two electrical leads within the socket when the bulb is not seated in the socket, the shunt being composed of a resistive material such that it provides a resistive element, the electrical power flowing through the resistive element when the bulb is not seated in the socket, the resistive element being matched to a resistive characteristic of the bulb so that the electrical power provided to the socket is substantially similar whether the electrical power is consumed by the bulb or the resistive element. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention. The embodiments illustrated herein are presently preferred, it being understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown, wherein: 
         FIGS. 1 and 2  show a first light string socket bridging arrangement containing a fixed resistive element according to one embodiment of the present invention; 
         FIGS. 3A-3B  show two different resistive elements on the light socket bridging elements according to various embodiments of the present invention; 
         FIGS. 4-7  show alternative light string socket bridging arrangements containing a fixed resistive element according to various other embodiments of the present invention; and 
         FIGS. 8-11  show alternative light string socket bridging mechanisms including a spring arrangement coupled with or as part of fixed resistive element according to various other embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     To facilitate a clear understanding of the present invention, illustrative examples are provided herein which describe certain aspects of the invention. However, it is to be appreciated that these illustrations are not meant to limit the scope of the invention, and are provided herein to illustrate certain concepts associated with the invention. 
     The present invention provides for the inclusion of a resistive element within the bridging mechanism that resides within a light string socket. The bridging mechanism and resistive element are an integral part of the socket and are external to the bulb. The purpose of the resistive element is to replicate, as closely as possible, the resistive characteristics of the bulb itself so that when the bulb is removed from the socket, the bridging mechanism accommodates the same load current being supplied to the socket. This enables the remainder of the light string to function under electrical conditions substantially equivalent to those experienced when the bulb is present in the socket. 
     It should be noted that the term bulb is used in this description to denote an electrically powered element that produces light. Although most of the disclosure is directed to incandescent bulbs found on light strings, those of skill in the art will recognize the teachings of the present invention to be applicable to any of a variety of electrically powered lights such as LEDs, phosphorescent bulbs, luminescent bulbs, and other electric bulbs. Further, is should be noted that a resistive element as used herein includes any electrically conductive resistor, or resistive element including but not limited to: a carbon resistor, surface mount resistor, a semiconductor material, carbon nanotube structures, a matrix resistive structure, or a resistive substance, coating or contact, etc. 
     The overall problem with not providing a resistive element of the type disclosed herein is that the overall light string, or series connected segment thereof, experiences an increase in current flow within the light string when a bulb is missing. In a series-connected electrical circuit, the missing bulb causes each of the remaining series connected bulbs to have the same supply voltage applied across their, now lower, total resistance. This is a result of Ohm&#39;s law, which for a series of serially connected resistors, R 1  through Rn, states: I=V/(R 1 +R 2 −R 3 +R 4 + . . . +Rn), where V is the supply voltage applied across the series-connected light string and I is the resultant current flowing through the light string. So it is clear from Ohm&#39;s Law that as the total resistance of the series-connected light string (R 1 +R 2 −R 3 +R 4 + . . . +Rn) decreases with the removal of each bulb, the current drawn by the overall circuit necessarily increases under a constant supply voltage. Commensurately, the voltage across each remaining resistor (bulb) also increases. Since the power (P) consumed by the bulb is given by the equation P=IV, and the current in the entire circuit increases with each missing bulb, the total power applied to the string as well as the power consumed by each bulb increases as bulbs are removed. Theoretically, this increases with each bulb removed until unsafe conditions are reached within the light string and a built-in fuse arrangement kicks in to stop current delivery or the overall light string system simply burns out and fails. 
     Many decorative light strings available on the market contain a shunting mechanism that is made of a highly conductive material (e.g. copper) having a low resistance in comparison to the resistive inductance of the light bulb that has been removed from the socket. Resistivity quantifies how strongly a given material opposes the flow of electric current and is a function of the geometry of the resistor. As one reference point, a 10 gauge AWG copper wire has approximately a 102 mil diameter and a resistance of approximately 1.018 Ohms per 1000 feet at temperature of 55 degrees Fahrenheit. In contrast, a typical light string bulb has a resistance of 7 to 8 Ohms through the filament. Shunts are also included within many light bulbs to permit current carrying through the bulb if the filament burns out. The inner-bulb shunt wire contains a coating that provides a fairly high resistance until the filament fails. At that point, heat caused by current flowing through the shunt burns off the coating and reduces the inner-bulb shunt&#39;s resistance. However, even after burn off, the bulb shunt still provides 2 to 3 ohms of resistance through the shunt once the coating burns off. Both of these values are significantly in excess of the resistance offered by the highly conductive materials currently used as shunts. Thus the need exists to provide a shunting mechanism within the light socket that more closely matches the resistance provided by the bulb filament such that the removal of one or more bulbs permits the continued illumination of the reaming light string bulbs without a significant increase in the light string current and power consumption. 
     The attached Figures illustrate various embodiments of light string sockets in which the removal of one or more bulbs on the light string still permit the remaining bulbs on the string to stay illuminated without the risk of increased current being applied to the remaining bulbs in the string. Such conditions are not only unsafe and fail to meet the newer electrical certification specifications, but they shorten the remaining bulbs&#39; life span and cause uneven illumination of adjacent, series-connected light string segments. 
     Referring to  FIG. 1 , a typical cross-sectional view of a light string socket  1  is provided in which the bulb assembly has been removed. Socket  1  includes a shunting mechanism  10  that bridges two inner-socket terminals  42  and  44  so as to provide electrical connectivity between them through the shunting mechanism  10 . Socket  1  further includes insulated lead wires  72  and  74  having wire leads  62  and  64  respectively that provide power to the light bulb socket via electrical coupling of the wires leads to the two inner-socket terminals  42  and  44  respectively. Wire securing wedge  90  is provided to secure mechanical placement of the lead wires  72  and  74  within the outer housing  50  of socket  1 . Attachment post  80  provides for uniform placement of the shunting mechanism  10  within the socket  1  such that proper registration of the shunt legs  12  and  14  is made with terminals  42  and  44  respectively and proper electrical connection between them is made at contact points  13  and  15  respectively. Once fully assembled and powered, current flows (depending on direction) from lead wires  72  and  74  through wire leads  62  and  64  across terminals  42  and  44 , and through shunt  10  so as to electrically connect the two socket lead wires and wire leads. 
     Shunting mechanism  10  is typically made of a highly conductive material such as copper. According to one preferred embodiment of the invention, a resistive sheath  20  may be applied at one or both ends of the shunt legs  12  and  14 . This sheath may, optionally, be further coated by an outer conductive sheath  30  applied atop one or both resistive sheathes  20  at the contact points  13  and  15  where the socket makes electrical connection with the shunt legs. Any one of a number of resistive coatings may be used such as a compressed carbon compound. Depending on the carbon composition and the geometric considerations of the resistive sheath, such as sheath thickness, resistive values of approximately 15-20 Ohms are achievable that are capable of safely handing ¼ watt of power. In yet another embodiment, the outer conductive sheath  30  is composed of copper flash plating that is applied to the ends of the shunt legs at connection points  13  and  15  to improve the connection with the copper or bronze terminals  42  and  44 . 
     Referring to  FIG. 2 , the light socket of  FIG. 1  is provided containing a light bulb assembly  100  having a lighting element or light bulb  105  a lighting element holder or light bulb holder  106  and light element or bulb leads  102  and  104 . Bulb leads  102  and  104  are electrically connected to the filament and/or inner-bulb shunt within bulb  105 , neither of which is shown in  FIG. 2 . Bulb leads are also arranged such that when bulb  100  is seated within socket  1 , e.g. bulb holder flanges  107  and  108  are flat against socket housing  50  and the bulb leads  102  and  104  are in electrical contact with leads  42  and  44  respectively. Also as shown in  FIG. 2 , mechanical biasing element  109  makes contact with leg  12  of shut mechanism  10  so as to push that leg inward toward the interior of the socket and out of electrical connection with terminal  42  thereby moving the shunt mechanism  10  and breaking the shunt&#39;s electrical connection within the socket. Once fully seated, current flows from lead wires  72  and  74  through wire leads  62  and  64  across terminals  42  and  44 , thorough bulb leads  102  and  104  and across the light bulb filament so as to illuminate the bulb. 
     Referring to  FIG. 3 , various arrangements of the shunt mechanism legs are provided. In  FIG. 3A , a shunting mechanism  10  having a leg  14  is shown. If the composition of the leg (and/or the entire shunting mechanism) is of a material possessing a high resistivity, i.e. higher than copper, then the singularly manufactured shunting mechanism itself my become the resistive element and can be used to replace existing light socket shunting mechanisms without further assembly or processing steps. Alternatively, shunt mechanism leg  14  may be coated with a resistive element  20  which may be comprised of a coating applied to the shunt leg by any of a number of plating, deposition or other adhesion processes. In turn, a conductive coating  30  (e.g. copper) may be further applied or deposited on top of the resistive element so as to provide better electrical contact with the socket terminal when the shunting mechanism is engaged. As shown in  FIG. 3B , an alternate location for the resistive element  220  is also show as a bead or dot  220  that is bonded to shunt leg  14  at the location of electrical contact with the socket terminals. 
     The key to the present invention is to substantially match the overall resistive characteristics of the shunt mechanism  10  with that of the bulb assembly such that the electrical current and power flow over the remaining portions of the light string remain substantially constant. Ideally, the resistive characteristics of the shunt mechanism at the two points of contact with the socket terminals is matched to the resistive characteristic of the bulb assembly at the same points. In one embodiment, the electrical resistance of the bulb assembly may simply be matched to that of the shunt mechanism. At the highest level of sophistication, the light bulb assembly may be a complicated structure containing microelectronic circuitry and numerous illumination elements. In this arrangement, the resistively profile of the light bulb assembly may be represented by a complex and dynamic resistivity function. It is this function that would be matched within the resistive element of the shunt mechanism so as to maintain consistent functioning of the light string. In practice, an exact matching between the resistively characteristics of the light bulb assembly and the shunting mechanism will neither be possible nor desirable. Rather, in practice, a substantial matching function will likely be implemented according to a metric by which the light string performance is measured. In this manner, and through the plurality of shunting mechanisms used within a light string, an acceptable variation about a mean current or power fluctuation may be accomplished during typical light string operation. 
       FIG. 4  provides yet another embodiment of the present invention. Here, similar to  FIG. 3B , resistive element  320  is provided as a bead or dot  321  that is bonded, in this embodiment, to the socket terminal  42  at the location of electrical contact  313  with the shunt mechanism leg  12 . The resistive element may be a resistive material such as a compressed carbon compound. The resistive element  320  is added to the terminals only in the area  313  where the shunting mechanism makes contact with the socket terminal but not in the area  317  in which the bulb terminals make contact with the socket terminals. The resistive element may be bonded to a conductive plate that is mechanically affixed to the terminal by a rivet like structure  322  or otherwise soldered to the terminal. 
       FIG. 5  shows a variation of the embodiment of  FIG. 4  in which the resistive element  420  is again affixed to terminals  42  and  44 . In this arrangement a higher resistivity material (e.g. carbon compound) is bonded to or otherwise deposited on to the terminals as part of the manufacturing process. A rivet-like structure or solder may be used to bond the resistive element to the terminal. Conductive contact plate  430  made of the same material as the conductive shunt mechanism may be further affixed to the resistive element. Again, the resistive element(s)  420  are so constructed such that the end-to-end contact resistance, as seen at the socket terminals, through the resistive elements and the shunt mechanism are substantially similar to the resistive characteristics provided by the light bulb assembly, which when inserted into the socket, disengages the shunt mechanism and any associated resistive elements. In alternative arrangements of  FIGS. 4 and 5  (not shown) only one terminal includes a resistive element which is properly configured and constructed according to the teachings of the present invention. 
     In  FIG. 6 , the shunt mechanism  10  is coated at the ends of the legs of the shunt mechanism, as described above. However, in this arrangement, the legs of the shunt mechanism are inverted (pointed up) and its leg ends bend inward towards the socket interior at the contact points  513  and  515 . In this manner, shunt mechanism legs provide contact with the socket terminals through the resistive coating  520  when the shunt is active and are pushed away from the terminals when the bulb seated in the socket 
     In  FIG. 7 , the inward bending terminals  642  and  644  are the shunting mechanism themselves and their spring activity causes them to come in contact it the middle of the socket at a single contact point  613  when the bulb is not seated in the socket. Higher resistance material (e.g. carbon compounds) provides the resistive element  620  as affixed to the terminals. As with the arrangements above, a separate conductive plate (not shown) may be bonded to the resistive element(s) which, in turn, are mechanically affixed to the terminal by a rivet-like structure or soldered to the terminal. 
       FIG. 8  provides for yet another light string socket to which the teachings of the present invention may be applied. In that embodiment, the socket terminals  742  and  744  have flange portions  743  and  745  extending into the socket cavity but allowing for a gap  746  to be formed therebetween. A plunger cartridge  759  having a bottom cartridge portion  758  is disposed within socket  701  between the flange portions  743  and  745  and a securing plate  756  disposed at the bottom of the socket. The plunger cartridge further contains outwardly extending flange portions  753  which, in one variation, may be a continuous circular shelf disposed around the top of plunger cartridge  759 . The flange portions extend outward from said plunger cartridge  759  so as to cause the upper surface area of the plunger cartridge to be larger than gap  746  left by the flange portions  724  and  727  of the terminals. 
     Spring element  757  is disposed around the outside of plunger cartridge  759  and is seated between outwardly extending flange portions  753  the on the top of the cartridge and the securing plate  756  disposed at the bottom of the socket. The spring provides upward force on the plunger cartridge  759  so as to place the plunger cartridge  759  in a fully upward extended position, causing the extending flange portions  753  of plunger cartridge  759  to contact flange portions  724  and  727  of the socket terminals when no light bulb assembly is seated in the socket. When a light bulb assembly is seated in the socket, plunger cartridge  759  is pushed downward thereby compressing spring element  757  and releasing the extending flange portions  753  of plunger cartridge  759  from contact with the flange portions  724  and  727  of the socket terminals. It should be appreciated that spring could also be disposed within the plunger cartridge  759  with appropriate provision of cartridge flanges so as to perform the same above-recited function. 
     In the embodiment of  FIG. 8 , the resistive element  710 , including resistive portion  720 , is placed within the plunger cartridge  759  and includes top lead  724  and bottom lead  727 . Top lead  724  extends from the top of plunger cartridge  759  above flange portion  753  so at to make electrical contact with flange portion  724  of socket terminal  744 . Likewise, bottom lead  727  extends from the bottom of plunger cartridge  759  up through the cartridge and extends outside the cartridge above flange portion  753  so at to make electrical contact with flange portion  743  of socket terminal  742 . The plunger cartridge top and bottom portions may be ultrasonically welded, glued or otherwise bonded together after the resistive element is inserted in the cartridge. Likewise, the securing plates  756  may similarly be bonded or ultrasonic welded to the side walls of the socket securing the spring and lead wires  772  and  774 . 
     In operation, when a light bulb assembly is inserted into socket  701 , plunger cartridge  759  is pushed downward compressing spring element  757  and releasing electrical connection of top lead  724  and bottom lead  727  of resistive element  710  from electrically bridging a connection between flange portions  724  and  727  of the socket terminals. In this position, upper side portions of the terminals  742  and  744  are in electrical connection with the bulb leads on the bulb assembly thereby providing electrical current and power to the bulb to illuminate it. (See  FIG. 10 .) When the bulb assembly is removed from the socket, plunger cartridge  759  is pushed upwards by spring element  757  causing electrical connection of top lead  724  and bottom lead  727  of resistive element  720  to form a bridging connection between flange portions  724  and  727  of the socket terminals. In this position, the current is passed through the resistive element and through the socket to other sequentially coupled sockets in the light string system. 
     After experimental evaluation, a resistive element  710  may comprise a simple, inexpensive carbon resistor having a value of 20 to 22 ohms and a power rating of ¼ watt. 
       FIG. 9  provides an alternative arrangement of the placement of the resistive element  810 . In this embodiment the plunger cartridge  859  is composed of a top portion  846  and a bottom portion  848 . Top portion  846  and a bottom portion  848  are threadably engaged to one another via threaded connections  849  disposed within both sections. Engagable slot  807  is provided at the bottom of the plunger cartridge  859  so that a screw driver or other tool may be conveniently used to securely enable the threadable engagement. Top portion  846  further includes the resistive element  810  which contains central portion  825  and resistive element leads  824  and  827  connected thereto. A resistor, resistive structure, resistive substance, resistive coating, surface mount resistor etc. ( 820  not shown) may be disposed anywhere within central portion  825  and electrically connected with leads  824  and  827  such that electrical connection is made between the flange portions of the socket terminals through resistive element  820  when the plunger cartridge  859  is fully pushed up (i.e. when the bulb assembly is removed). Otherwise the operation of the embodiment of  FIG. 9  is substantially similar to that provided with respect to  FIG. 8 . 
       FIG. 10  provides the light  801  socket of  FIG. 9  with the light bulb assembly  900  inserted into the socket  801 . Light bulb assembly includes lighting element holder or light bulb holder  906  and light element or bulb leads  902  and  904 . Bulb leads  902  and  904  are electrically connected to the filament and/or inner-bulb shunt within bulb  905 , neither of which are shown in  FIG. 10  and are also connected to socket terminals  842  and  846  so as to provide power to the light bulb assembly. In the seated position, the bottom end of light bulb assembly  910  pushes the top portion of the plunger cartridge  859  down causing spring element  857  to compress thereby releasing resistive element  820  from electrical connection to the terminal flanges. 
       FIG. 11  discloses an embodiment in which the spring element  857  itself is the resistive element  810 . The spring element  857  can be made of any of a number of semi-resistive or semiconductor materials, or a high resistance metallic alloy including, but not limited to, a nickel chrome alloy, or spring element may be coated with resistive coatings either over the entire spring or at its connective ends. Leads  1024  and  1027  are coupled to spring element, one at each end, and the socket terminals and provide electrical connection across those terminals through spring element  857 . Alternatively, one or more of the leads  1024  and  1027  themselves may be the resistive element  810  with the spring being left as a natural copper conductor. 
     With respect to creating resistive structures about conductors, one method of applying a carbon compound resistive coating to a wire is to place the formed wire in a mold, close the mold and inject a slurry of the compound into the mold to fill the cavity desired around the wire. While in the mold, the mold and wire are heated for a specific time period at a specific temperature. Depending on the chemicals and chemical processes being used, the resultant compound can be made to bond to the wire. After boding, a plating process may be used to provide the outer conductor wherein the wire ends are placed in a copper plating bath with an electrical bias applied to the bare wire end causing the copper plating to adhere to the carbon compound. 
     With respect to the deposition of resistive materials onto a conductive element to create the resistive element of the present invention, any of the heretofore known or later developed methods of material deposition/adherence may be used. For example, one method of applying a carbon compound resistive coating to a wire is to place the wire in a vacuum chamber, with the area not to be coated masked off, and exposing the remaining wire to a heated vapor cloud of the carbon compound with a positive bias on the masked end of the wire. When the vapor cloud having positively charged partials is subject to the electrical field, its particles are caused to adhere to the unmasked portions of the wire. The process is extended until a desired thickness of carbon is deposited on the wire. After removal from the chamber, additional chemical vapor deposition (CVD) processes may be exercised to plated additional conductive and resistive materials on the wire. 
     In addition to CVD techniques, sputtering, sintering, electron beam, x-ray lithography and various other chemical deposition techniques may be employed to create resistive structures as contemplated according to the teachings of this invention 
     While the invention has been shown and described with reference to specific preferred embodiments, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the following claims.