Decorative light string

#The present invention relates to decorative lights, including lights for Christmas trees, including pre-strung or “pre-lit” artificial trees.

#In accordance with the present invention, one or more strings of decorative lights are supplied with power by converting a standard residential electrical voltage to a low-voltage, and supplying the low-voltage to at least one pair of parallel conductors having multiple decorative lights connected to the conductors along the lengths thereof, each of the lights, or groups of the lights, being connected in parallel across the conductors. A string of decorative lights embodying this invention comprises a power supply having an input adapted for connection to a standard residential electrical power outlet, the power supply including circuitry for converting the standard residential voltage to a low-voltage output; a pair of conductors connected to the output of the power supply for supplying the low-voltage output to multiple decorative lights; and multiple lights connected to the conductors along the lengths thereof, each of the lights, or groups of the lights, being connected in parallel across the conductors. The lights preferably require voltages of about 6 volts or less, and are preferably connected in parallel groups of 2 to 5 lights per group with the lights within each group being connected in series with each other.

#The parallel groups are useful for current management. Light strings typically have 100 bulbs, and 100 6-volt bulbs drawing 80 ma./bulb in parallel requires a total current flow of 8 amps, which requires relatively thick wires. With the parallel groups, the total current and the wire size can both be reduced.

#The invention may best be understood by reference to the following description taken in conjunction with the accompanying drawings, in which:

#FIG. 1 is a schematic diagram of a string of decorative lights embodying the present invention;

#FIG. 2 is a more detailed diagram of the light string shown in FIG. 1;

#Although the invention will be described next in connection with certain preferred embodiments, it will be understood that the invention is not limited to those particular embodiments. On the contrary, the description of the invention is intended to cover all alternatives, modifications, and equivalent arrangements as may be included within the spirit and scope of the invention as defined by the appended claims.

#Turning now to the drawings and referring first to FIGS. 1-3, a power supply 10 is connected to a standard residential power outlet that supplies electrical power at a known voltage and frequency. In the United States, the known voltage is 120 volts and the frequency is 60 Hz, whereas in Europe and some other countries the voltage is 250 volts and the frequency is 50 Hz. The power supply 10 converts the standard power signal to a 24-volt, 30-KHz output, which is supplied to a pair of parallel conductors 11 and 12 that supply power to multiple 6-volt incandescent lights L. A typical light “string” contains 100 lights L.

#Multiple groups of the lights L are connected across the two conductors 11 and 12, with the lights within each group being connected in series with each other, and with the light groups in parallel with each other. For example, lights L1-L4 are connected in series to form a first light group G1 connected across the parallel conductors 11 and 12, lights L5-L8 are connected in series to form a second group G2 connected across the conductors 11 and 12 in parallel with the first group G1, and so on to the last light group Gn.