具体实施方式：
Socket
[0261] One aspect of the invention relates to improvements in the manner in which lamps are accommodated in lighting fixtures.
[0262]FIG. 1A illustrates prior art.
[0263] The light source illustrated is incandescent, and comprises a filament 90F supplied with power via two conductors 90G and 90H. Dashed line 90E indicates the lamp's envelope and, in this Figure, is attached to a lamp “base”90B that mounts two electrical contacts 81 and 82 that form the electrical interface between the conductors 90G and 90H of lamp 90 and power.
[0264] These lamp-side electrical contacts 81 and 82 are illustrated as capable of coming into an electrically conducting relationship with contacts 61 and 62, which can be mounted in a common lamp “socket”50 on the supply side of the interface. (In some embodiments, as illustrated here, contacts are adjacent in the same base and socket, while in others, mating contact pairs are located, for example, at opposite ends of a tubular envelope.)
[0265] In this simple representation, the supply-side contacts 61 and 62 are shown connected with the electrical power source 17. An additional set of contacts 31 and 32 that mate with contacts 25 and 26 are illustrated and may represent the contacts of a connector pair, for example, at the end of a fixture's power lead. There can also be additional components for functions that can include over-current protection/power distribution; power control/dimming; and/or (in the case of gas discharge sources) power conditioning and starting.
[0266] Most lighting fixtures are capable of accepting any one of a plurality of different available lamp variants. In the case of incandescent sources, lamps may differ in one or more of several characteristics, including in their design operating voltage (for example, for use on different local voltages); in wattage; and/or in design life at a given wattage and voltage combination (for example, several hundred hours for applications where output is desired; or a thousand hours or more where longer life and fewer lamp changes are the priority).
[0267] Such lamp variants generally share the same envelope design, light center, and base design to assure their physical and optical interchangeability in the same fixture. The manufacturer relies upon the user to employ a lamp suitable for the application.
[0268] In some cases, where different lamps might be stocked and used by a given facility or vendor and their characteristics differ sufficiently that the accidental insertion of the “wrong” lamp variant or its connection to the “wrong” input power could result in damage to the lamp and/or to the fixture, provision may sometimes be made to reduce the likelihood of such errors.
[0269] In one example, the Source Four ellipsoidial from Electronic Theatre Controls of Middleton, Wis. (as is generally described in U.S. Pat. Nos. 5,446,637 and 5,544,027) is available with a range of lamp variants include not only the previously-described variations in line voltage, wattage, and design operating life, but also in a half-wave variant that is used with the “multiplexing” system described in U.S. Pat. No. 5,323,088. (The half-wave lamp for a 120-volt system is a 77-volt variant, but it will be understood that the actual lamp design voltage for other than 120-volt power systems will differ.) The direct connection of a half-wave lamp to normal line voltage will result in its rapid failure. The “dimmer doubler” unit (identified as 3B in the '088 patent) being separately packaged, the probability of so connecting a fixture with a half-wave lamp are reduced by using a different electrical power connector on all half-wave portions of the system; one incompatible with the various connector types used for line-voltage applications. Like most “lekos”/ellipsoidials, the Source Four fixture uses a “lamp cap” to which both the lamp socket and the fixture power lead are permanently attached. (The lamp cap is identified as “burner assembly 23” in the '637 patent, the socket is 77, and the power lead is 72.) Therefore, the half-wave system requires use of a lamp cap identical to the line-voltage version, except that its power lead is terminated in such an incompatible connector. The same connector is employed on the outputs of the “dimmer doubler”, and is required for the intermediate extension cables needed when the two fixtures supplied from a common “dimmer doubler” are not immediately adjacent.
[0270]FIG. 1B illustrates. Lamp 90 is a line-voltage variant. Lamp 91 is a half-wave variant. The conductors 41A and 42A of power lead 40A are attached to socket 50A and terminated at the supply end in a “stage-pin” type plug 30A as is often employed on line-voltage portions of a lighting system. The power lead 40B attached to socket 50B is terminated in a twist-lock connector 30B of a configuration limited to use on half-wave portions of the “multiplexed” system. (In these and most other embodiments, provisions will also be made for a safety ground.)
[0271] While reducing the likelihood of an accidental connection of a fixture with a half-wave lamp directly to line voltage, this approach has several disadvantages. Because field exchange of connectors on the same power lead is not practical, separate lamp caps with different power connectors are required if the same fixture is to be used in both half-wave and line-voltage modes, resulting in the need to stock additional lamp caps at significant cost, as well as is the need to physically exchange lamp caps (and not just lamps) to convert the same fixture between the two modes. The separate “dimmer doubler” unit is also required, as are specialized extension cables, should the two fixtures sharing a “dimmer doubler” not be (or remain) physically adjacent.
[0272] Also, because the lamp variants in this system are physically interchangeable, nothing prevents the accidental insertion of a half-wave lamp (e.g., lamp 91) in the socket (e.g., socket 50A) of a line-voltage lamp cap, which will generally only be discovered when application of line voltage destroys such a lamp.
[0273] The same ETC Source Four fixture design was also upgraded after its introduction to accept a 750-watt lamp, in addition to the 575-watt lamp that had previously represented the fixture's upper wattage limit. To prevent use of the 750-watt lamp in older fixtures, the 750-watt version has a lamp cap whose lamp socket, while otherwise similar to that for the 575-watt fixture, incorporates a recess that will accommodate an additional, non-conducting, pin that projects from the base of the 750-watt lamp. The 575-watt lamp socket, lacking such a recess, will not accept a 750-watt lamp.
[0274]FIG. 1C illustrates. Lamp 90 and socket 50A are the 575-watt variant also seen in FIG. 1B. Lamp 92 and socket 50C are the 750-watt variant with pin 92P and recess 50C illustrated.
[0275] Beyond the issues that attend the need for such lamp variants in fixtures, can also be those of employing lamps operating on very different principles in the same fixture; for example, to employ at least one incandescent source, as well as at least one gas discharge source, for reasons that can include differences in lamp life, replacement cost, power efficiency, color rendering, and/or for matching color temperature with other fixtures having the same type of source.
[0276] Even were lamps of these different types to be physically and optically interchangeable, their electrical requirements are generally very different. As in the half-wave example, the use of the “wrong” lamp (for example, an incandescent lamp on the igniter and ballast for a gas discharge source) is undesirable; yet minimizing the variations in a fixture necessary to accommodate different source types is very desirable.
[0277] Refer now to FIG. 1D. Like the prior Figures, two lamp variants 93 and 94 are illustrated, as is a socket 50D. Unlike the prior Figures, the socket is illustrated with at least one additional electrical contact on the supply side of the interface.
[0278] It will be seen that, when lamp 93 is employed, filament 93F will appear, via lamp base contacts 81D and 82D, between socket contacts 61D and 62D. When lamp 94 is substituted in the same socket 50D, its filament 94F will appear, via lamp base contacts 81E and 82E, in an electrical circuit between socket contacts 61D and 63D.
[0279] Therefore, while lamps 93 and 94 may be made optically and mechanically interchangeable, the insertion of one or the other lamp results in different electrical circuiting. Such different electrical circuiting can be used to protect each lamp, if not to provide for its connection to the appropriate power.
[0280] In any of the embodiments herein and in others, many techniques can be used to protect lamp variants and/or to assure the “correct” supply of power, including variations in contact size, shape, orientation, and number, and in features of the lamp base and socket configuration. In the case of a design like that disclosed in design patent D477,885 S, different contacts can be located at different radiuses from the lamp's central axis and/or in different planes perpendicular to it. (While FIG. 1D illustrates three contacts on each lamp base (e.g., contacts 81D, 82D, and 83D on base 93B of lamp 93) it will be understood that the unused contact(s) can be omitted. It will also be understood that “backward-compatible” designs are possible in which some existing lamp and lamp base designs can be employed.)
[0281] The additional contact(s) can be wired to the appropriate pole of a different power connector, such that a circuit will result only when the appropriate lamp is connected with the appropriate power.
[0282]FIG. 1E illustrates.
[0283] Contacts 61E and 62E of socket 50E are wired to “stage-pin” connector 30A. Contacts 61F and 63F of socket 50F are wired to “twist-lock” connector 30B. Unlike the prior art approach of FIG. 1B, insertion of a bulb in the “wrong” assembly will not result in a circuit on the “wrong” power system and, therefore, in damage to lamp or fixture.
[0284] In FIG. 1F, a socket 50F is mounted with a power inlet connector 36, and the two may be either mounted in or readily removable from fixture housing 5F. Power leads can be terminated in a connector mating with the power inlet connector 36 on one end (e.g. 35G) and terminated with the desired power connector (e.g., “stage-pin” connector 30A) on the other. Such power leads are less expensive than the present complete lamp cap assembly and can be readily exchanged for another assembly terminated in the same or a different (e.g., twist-lock 30B) power connector. The lamp socket and power inlet connector can be separate components or can be fabricated in a unified assembly.
[0285] In FIG. 1G, the power lead 40G terminates in an assembly 51A that provides the lamp socket function, but can be readily removed and replaced. Power lead 40G is shown terminated at the other end in a “stage-pin” connector 30A, and the entire assembly can be readily removed from the lamp housing 5G, in this example, by pulling latch 6G, which withdraws plunger 6GP from a recess 51AR in assembly 51A. Thus, the entire electrical system can be quickly replaced with a similar or a different assembly.
[0286] In these examples, it will be understood that an electrical circuit will result only when a power lead having the appropriate power connector is used with an appropriate lamp—for example, when a line-voltage power lead is used with a line-voltage lamp.
[0287] The techniques disclosed can be employed with many different lamp variants, including, but not limited to, half-wave variants. As will be seen, they can be employed with lamps of different types.
[0288] The Figures following include some of the techniques that permit half-wave lamp variants to be used without requiring either specialized “dimmer-doublers” or connectors.
[0289] In FIG. 1H, the necessary diode(s) is integrated at the fixture, rather than in a separate unit. As will be seen, the insertion of a line-voltage lamp 93 in socket 50H results in its connection to line-voltage connector 30A. The insertion of a half-wave lamp 94 in the same socket also results in its connection to line voltage, but via the necessary diode. A double-pole, double-throw switch 72 allows selecting diode polarity and, therefore, the assignment of the lamp to one side or the other of a “multiplexed” dimmer. (Alternatively, a single diode whose polarity of insertion is changed by a switch or other means can be employed.)
[0290] It will be understood that the reversing function can be provided by means other than a physical switch. For example, if a power inlet connector similar in principle to inlet connector 36 of FIG. 1F is employed, its design could permit two or more orientations of mating, which could be employed to change circuiting and, therefore, polarity.
[0291] Refer now to FIG. 1I, which illustrates several techniques that can be employed separately or together in the illustrated and in other embodiments.
[0292]FIG. 1I illustrates the use of a bipolar semiconductor power control means inserted in series relationship between the supply (via connector 30A) and the lamp socket 50I. In this embodiment, inverse-parallel thyristors are illustrated, although other devices and/or other topologies can be employed. It will be apparent that the power semiconductor means can be used to accommodate both line-voltage and half-wave bulbs by the simple expedient of causing it to conduct in half-cycles of one or both polarities, and that reversing polarity is trivial. Thermal losses in the device(s) are limited and there are no potential EMI/RFI issues, as any mode changes can be performed at the zero-crossing.
[0293] A semiconductor power control means at or near the fixture providing selectable full-wave and half-wave operation can also be used in intensity control.
[0294] The mode(s) of operation of such a semiconductor power control means in intensity control can be one or more of many and can be varied.
[0295] For example, the use of known “skipped half-cycle” techniques requires no significant increase in either parts cost or thermal losses, providing a measure of intensity control that can be suitable in some applications.
[0296] Thyristors can be used with an inductor for phase-control. Field-effect devices/IGBTs can be operated in linear, controlled-transition, and/or PWM modes.
[0297] It will be understood that the mode of operation of such a semiconductor power control means can be made responsive to the lamp variant and/or to the desired intensity relative to the supply voltage.
[0298] A common semiconductor power control means can be used with provisions to add or exchange the additional components required for intensity control, including drive electronics, inductors, and other additional components, and/or additional heat sink or heat dissipation provisions.
[0299]FIG. 1I illustrates a control means 75 that drives the power devices 73A and 73B via their gates on line 73C. Control means 75 is illustrated as sensing voltage/power waveform via input 75V and current from sensor 75C. It also illustrates an input 75I for a desired intensity value and one from a sensor 75S, that sensor illustrated at lamp socket 50I.
[0300] While the circuiting of a fixture can be changed as a consequence of the use of different circuit paths at the electrical interface to the lamp, such is hardly the only method of identifying lamp variants and controlling the power applied. Additional contacts on or physical or other features of the lamp can be used to identify lamp variants—for example, feature 93N is detected by sensor 75S when lamp 93 is inserted in socket 50I. The very differences between lamp variants that result in their differing power requirements can produce detectable differences in their response (for example, impedance/current demands) that can be non-destructively tested for and operation adjusted accordingly.
[0301]FIG. 1J is a detail of one example power device alternative; a single field-effect device 74D inserted in a diode bridge comprising diodes 71C, 71D, 71E, and 71F, which permits its bipolar operation.
[0302] In any of these or other embodiments, the semiconductor power control means and/or control means can be packaged in one or more readily replaceable modules(s).
[0303] In any of these or other embodiments, the semiconductor power control means could be packaged in or insertable in the fixture; separately from the fixture in, for example, an enclosure installed in-line in an attached or a removable power lead; or packaged in an independent enclosure.
[0304] Where prior Figures make changes on the supply side of the lamp interface to change half-wave polarity, FIG. 1K illustrates polarity change by the simple expedient of changing the orientation of the lamp in the socket. When line-voltage lamp 93K is inserted in socket 50K it is directly connected to line voltage via 41K and 42K. With half-wave lamp 94K inserted in socket 50K in the orientation illustrated, lamp 94K will be connected to the same line-voltage connector 30A, but via diode 71H. By reversing the same half-wave lamp 94K upon its insertion in socket 50K, lamp contact 83K will mate with socket contact 64K instead of socket contact 63K, resulting in a connection to line voltage via diode 71G, and, therefore, in reversed polarity.
[0305]FIG. 1L incorporates the diode required by half-wave operation at the lamp itself. Base 94LB of lamp 94L inserts diode 71I in the circuit path between contact 82L and filament 94LF. The contacts 61L and 62L of socket 50L can be connected directly to line-voltage (or such other power source as desired). Insertion of lamp 93L in socket 50L results in its direct connection. Insertion of lamp 94L in the same socket 50L will always insert the required diode in series. Reversing lamp 94L in socket 50L will reverse diode polarity and, therefore, “assign” the lamp to the other side of the “multiplexed” dimmer supplying it.
[0306] Diode 71I may be made integral with the lamp. As previously described, one or more semiconductor power control devices can be used in lieu of a diode(s). In lamp-designs like that illustrated in U.S. D477,885 S, rotation of the bulb about its central axis between one and the other of two “locked” positions/orientations (in addition to at least one “insertion” position/orientation) can produce diode reversal Such lamp designs can include a portion external to the fixture housing operating at substantially lower temperatures than portions within the fixture housing. Diode 71I can be located at this exterior portion, if not provided with a heat sink there.
[0307] In the “multiplexed” system as has been described, a given half-waved lamp filament is coupled to the alternating-current supply only during half-cycles of one polarity. It is, therefore, necessary that the lamp loads be divided/assigned between the two polarities, to make efficient use of dimmer and circuit and to achieve the object of separate control of lamp intensities on the same dimmer output.
[0308] It is further necessary that the control electronics of the dimmer supplying such lamps and the lighting controller sending desired intensity values to that dimmer both be re-configured to provide for separate control of the two “sides”/polarities of the dimmer's output.
[0309] At present, both the assignment of lamps to one or the other “side”/polarity and the re-configuration for “multiplexed” operation require the intervention of the user.
[0310] Both such re-configuration and the assignment of half-wave bulbs to one or the other “side”/polarity can be simplified, if not made automatic.
[0311]“Half-waved” lamp filaments conduct only in half-cycles of one polarity. Therefore, if only a single such lamp is connected to a dimmer, continuity will be “seen” through a half-waved filaments in only half-cycles of one polarity, where one or more line-voltage filament will conduct in both. When multiple half-waved filaments are connected via diodes in both polarities (i.e., to both “sides” of the dimmer), other methods of detection can be employed. The impedance and/or the current demands of the connected lamp load can be determined, using, for example, a sensor at the dimmer power stage level or one shared by multiple dimmer power stages. Differences between the impedance/current demands on either “side” of the dimmer power stage can be sensed or inferred to-detect the presence of “multiplexed” lamps. For example, if different total half-waved filament wattages are connected to the two “sides”, the difference can be detected and “multiplexed” operation deduced. Regardless of the relative wattage “balance” of connected half-waved lamps between the two “sides” of a dimmer, the impedance of a lamp filament changes dramatically between its “cold” state and its energized, “warm” state, such that half-waved lamps can be detected by applying power differently to half-cycles of different polarity. If half-waved lamps are attached, a detectable difference can be created in load impedance/current demands by “cooling” filaments on one side and “warming” those on the other. If such differences appear, “multiplexed” operation can be deduced. If one or more line-voltage lamps are connected, no significant difference in impedance/current demand will be apparent between the lamp load in two nearby half-cycles of opposite polarity. Upon detection of half-waved (or line-voltage) lamps on the dimmer output, the corresponding configuration adjustments by both dimmer and controller can be made automatic.
[0312] The insertion and/or the polarity selection of a diode in series with a lamp can also be made automatic, either as a strictly local operation or in cooperation with other components of the lighting system.
[0313] The assignment of “multiplexed” fixtures to one or the other polarity can be made by the user at the fixture, for example by the use of a mechanical switch, a mode selection, or changing lamp orientation.
[0314] It is also possible to make such assignment automatic and/or remotely modifiable. For example, the current demands of an energized lamp load on a circuit will typically result in a voltage drop as a result of losses in cable and dimmer chokes, relative to the same lamp load's un-energized state. By connecting a half-waved lamp to first one and then to the other polarity of half-cycles, it can be determined from the resulting relative voltage drop whether another such half-waved lamp is also present on the same circuit, and if so, on which polarity, and the other polarity selected. (As in collision sensing digital addressing schemes, differing time bases can be used in sampling.)
[0315] Polarity selection can be made or altered remotely.
[0316] For example, the applicant's U.S. Pat. Nos. 6,211,627 B1 and 6,469,457 B2 discloses methods by which values can be encoded in dimmer outputs, for example, by relative variations in average power passed in different half-cycles. Such techniques can be used to signal means associated with the fixtures (in only one example, control means 75 of FIG. 1I) to, for example, interrogate them as to the lamp variant connected. Such circuits can respond by connecting or not connecting or by delaying the connection of the lamp load so as to be detected. Encoded instructions can be used to remotely set and change fixture polarity/half-cycle. Other methods of communication can be employed.
[0317] The disclosed detection and polarity-setting techniques can be used whether the device(s) “half-waving” lamps are packaged with or independently of the fixture.
[0318] As earlier described, there is also frequently the desire, if not the need, to operate not just variants of lamps of the same type, but lamps of completely different types (for example, both incandescent and gas-discharge lamps) in the same fixture, although their power requirements and the auxiliary equipment that they require can be very different and often incompatible.
[0319] Any of the techniques of the present invention can be employed to achieve this object.
[0320] Refer now to FIG. 1M, an embodiment in which, for example, an incandescent lamp 93M or a gas-discharge lamp 95 can be employed. In this embodiment, (phase-to-neutral) lamp-side contacts 81M and 82M of incandescent lamp 93M mate with supply-side contacts 61M and 62M of socket 50M. If, on the other hand, gas-discharge lamp 95 is employed, its lamp-side contacts 85M and 86M mate with supply-side contacts 65M and 66M of socket 50M.
[0321] Therefore, either lamp type can be inserted in the same socket, but different circuiting results.
[0322] The additional components/auxiliary equipment in the circuit path for each lamp type, as well as the input power connection, can differ. In the illustrated embodiment, for example, incandescent lamp 93M is supplied with line voltage via 41M and 42M from a typical phase-to-neutral connection between phase 17Z and neutral 17N of source 17. However, if gas-discharge lamp 95 is inserted in socket 50M, it will be supplied via 76C and 76D from a ballast and igniter 76 which, in turn, is supplied a higher input voltage by a phase-to-phase connection via 76A and 76B between phase 17Y and 17Z.
[0323] Separate contacts are illustrated here for the two lamp types. It will be understood that some contacts can-be shared between different lamp types. It will also be understood that additional contacts or other features may also be provided for variants within lamp types, such as between line-voltage and half-wave incandescent lamps.
[0324] In FIG. 1M, the supply of power to both “sides” of the system are illustrated as different, in that line voltage will typically be applied to at least some incandescent lamp variants, and at least the option of higher voltage (phase-to-phase) operation can be both practical and desirable for gas discharge sources. In the context of FIG. 1F, it will be understood that different power leads could be employed to assure that, for example, a phase-to-phase supply could not be connected to the incandescent lamp 93M. (In these and other cases, a ballast for gas-discharge lamps will often be capable of operating on either connection.)
[0325] Referring now to FIG. 1N, an embodiment is illustrated in which one “side” includes auxiliary equipment 76 for gas discharge sources and the other includes a semiconductor power control means 73N that permits use of either line-voltage or half-wave incandescent lamps and/or intensity control. In this or other embodiments, such a semiconductor power control means can be used to permit operation of an incandescent lamp from a supply voltage well in excess of the lamp's design voltage (a voltage that might be preferred for the gas discharge source).
[0326] In FIG. 1N, an embodiment is also illustrated in which at least two different lamp types can be accommodated and both “sides” are connectorized to permit the insertion/exchange of auxiliary-equipment. The types of equipment on each “side” can be varied—for example, a fixture might permit the use of multiple gas discharge source types operating on different principles, and therefore, potentially requiring different auxiliary equipment. Different such equipment can be inserted/attached, depending upon the requirements of the light source employed. The previously-described or other techniques can be employed to assure that the appropriate power is applied to a given lamp.
[0327] Where FIG. 1N illustrates an embodiment in which separate power conditioning/power control apparatus are provided on a plurality of “paths” between a lamp and power, there will be cases where there is potential commonality between the components required by different lamp types. FIG. 1O illustrates an embodiment in which a common portion 77 is shared between multiple lamp types. Certain additional elements (for example, high-voltage igniter 78) may be required for only one type of lamp (if not being undesirable for another). Such elements can be located in separate circuit “paths”, as is illustrated—or their connection or operation may be made conditional upon the previously described connection or sensing of the appropriate lamp type and variant.
[0328] In every illustrated and in other embodiments, the lamp or an adapter or carrier used with it can incorporate one or more feature that changes circuiting and/or changes the state of a supply-side sensor, resulting in the protection of the lamp, if not the application of the appropriate power to it. Alternatively, the differing characteristics of different lamp types and variants permit the use of techniques that apply power to identify the type of lamp (if not the variant within that type) without applying potentially destructive voltages and/or currents.
[0329] The techniques employed to achieve the benefits of the invention should not be understood as limited except by the claims.
[0330]FIG. 1PA-1PI illustrate but one of many possible embodiments, in this case, of a traditional “single-ended” lamp design.
[0331] The example employs a variation in the design of base and socket to limit the orientations in which a lamp can be inserted. FIG. 2PA, a frontal elevation of the lamp socket, and FIGS. 2PB and 2PC, which are sections, the planes of which include the lamp/socket centerline, and are at right angles to each other, illustrate an extended “collar”50PC forming a well into which the lamp base is inserted. That “collar” has a curved face 50PA, and flatted sides 50PC, that prevent the insertion of lamp bases 93PB and 95PB unless their flatted sides are parallel to those of the socket “collar”.
[0332] Lamp base 50P is illustrated with five contact wells, for contacts including 61P, 62P, 65P, and 66P. It will be seen from examination of the Figures that lamp 95P (which is shown from two sets of angles rotated 90 degrees), when inserted in socket 50P, will mate pins/contacts 85P and 86P only with socket contacts 65P and 66P. In the other hand, the pins/contacts 81P and 82P of lamp 93P will mate only with socket contacts 61P and 62P. Thus, lamps 93P and 95P will be circuited separately as in, for example, FIGS. 1M and 1N.
[0333] As illustrated, either lamp can be inserted in two possible orientations, each rotated 180 degrees from the other. This might provide, for example, the diode reversal of FIG. 1L. It will be apparent that variations in base/socket and/or contact design (among other techniques) might prevent an undesirable such reversal.
[0334] FIGS. 1QA-1QD illustrate example techniques applied to a different lamp base configuration. It will be seen that contacts 65Q and 66Q of the base 95QB of lamp 95Q are at a different radius from the centerline of lamp 95Q, relative to contacts 81Q and 82Q of lamp 93C, such that they will mate with different socket contacts and different circuiting will result. It will also be apparent that either lamp can be inserted in a socket and rotated 180 degrees in one direction or the other to produce two different circuiting alternatives—including a diode reversal. The use of techniques including lamp base and socket features and contact design can be used to limit the mating orientation.
[0335] Where prior Figures have illustrated lamps having a single, fixed power requirement, FIGS. 1R and 1S illustrate lamps that have a plurality of possible power requirements based on variable circuiting.
[0336] In FIG. 1R, lamp 96 has at least two filaments or filament segments 96F and 96FF, with three illustrated conductors 96G, 96H, and 96I and three contacts 81R, 82R, and 83R to an external source of power via socket 50R. It will be understood that connecting power to contacts 41R and 42R will energize only filament 96F; that connecting power to contacts 42R and 43R will energize only filament 96FF; and that connecting power to contacts 41R and 43R will energize both filaments in series.
[0337] Thus, lamp 96 could be operated on at least two very different power services.
[0338]FIG. 1S illustrates a lamp 97 that provides even greater flexibility. Filament 97F is circuited (via conductors 97G and 97J and by the socket contacts 61S and 64S that mate with them) independently of filament 97FF. Thus, by varying the circuiting of conductors 41S-44S, filaments 97F and 97FF can be used independently; in parallel; or in series, further increasing versatility