Christmas light string with silicon triggered switch shunts

Abstract

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 bulbs in the string are either inoperative or are missing from their respective sockets.

1 . A filament shunted light string comprising the combination of: 
 a plurality of electrical bulb supporting sockets connected in an electrical series circuit arrangement with each other and adapted to be energized by an electrical potential connectable to input terminals thereof, and with each of said sockets being adapted to have an electrically operable miniature incandescent lamp for Christmas tree lighting and decoration inserted therein and are illuminated whenever said electrical potential is applied to said input terminals; and    voltage responsive switching means consisting of a silicon trigger switch device connected in parallel across each of said sockets to maintain current passing through the light socket in the event that a light bulb is inoperative or is missing from the light socket, whereby all illuminated bulbs in said string continue to receive current therethrough and continue to be illuminated and the voltage drop across each bulb and the brightness of each bulb remains substantially unchanged, even though multiple bulbs in the string are not illuminated for whatever reason, or are actually missing from their respective sockets.    
   
   
       2 . The light string of  claim 1 , comprising  50  electrical bulb supporting sockets for receiving 50 bulbs.  
   
   
       3 . The light string of  claim 1 , wherein the electrical potential is 120 volts AC.  
   
   
       4 . The light string of  claim 1 , wherein the electrical potential is full-wave rectified and filtered pulsating DC.  
   
   
       5 . The light string of  claim 1 , further comprising light bulbs disposed in each of said sockets.  
   
   
       6 . The light string of  claim 1 , wherein said light bulbs are miniature incandescent bulbs that draw a current up to approximately 200 milliamperes each, resulting in a power dissipation per bulb equal to or less than approximately one watt.