Patent attributes
A string set of series-connected incandescent bulbs in which substantially all of the bulb filaments in the set are individually provided with a shunt circuit which includes a voltage responsive switch which is inoperative during normal operation of the string set when connected to a source of operating potential and which becomes operative only in response to an increase in the voltage thereacross which exceeds its rating, and in which the remaining bulbs of the circuit continue to receive substantially rated current therethrough and substantially rated voltage thereacross and further continue to be illuminated at substantially constant illumination even though other or substantially all of the other bulbs in the string are either inoperative or are missing from their respective sockets. If flasher bulbs are used in the string, they will twinkle off and on when the operating potential is applied.
