Patent Publication Number: US-2010109538-A1

Title: Continuous current control circuit modules of series string bulbs type

Description:
This application is a continuation-in-part of U.S. application Ser. No. 11/062,835 filed on 23 Feb. 2005, now U.S. Pat. No. 7,242,148. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to an improvement of a continuous current control circuit module of series string bulbs, which includes a secure shunt for maintaining electrical connection of the light string effectively. 
     BACKGROUND OF THE INVENTION 
     In prior art, continuous current control circuit modules of series string bulbs in order to maintain their electrical connection whenever any bulb assembly is broken or loosen have different structures, such as U.S. Pat. No. 6,323,597, U.S. Pat. No. 5,731,667, and U.S. Pat. No. 5,886,423. In these structures, as shown in  FIGS. 1 to 3 , they include large volumes and are complicated, which will not be capable easily to be assembled the electronic pieces in such tiny space of a decorative bulb ( FIG. 4 ). Or it needs high cost to complete such assembly. Therefore, the said patents are lack somehow of utility. 
     SUMMARY OF THE INVENTION 
     The present invention is based on U.S. Pat. No. 7,242,148 to provide an improved continuous current control circuit module of series string bulbs having secure shunt, which uses Zener diode having a small volume to replace previous TRIAC (THYristor) in each circuit module to obtain the effect of improvement. Now, accompanying with the following drawings, the character of the present invention will be described here and after. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view showing an electrical circuit of U.S. Pat. No. 5,886,423. 
         FIG. 2  is a schematic view showing an electrical circuit of U.S. Pat. No. 5,731,667. 
         FIG. 3  is a schematic view showing an electrical circuit of U.S. Pat. No. 6,323,597. 
         FIG. 4  is a cross-sectional plan view showing a bulb assembly according to the present invention. 
         FIG. 5  is a schematic view showing an embodiment of an electrical circuit according to the present invention. 
         FIG. 6  is a schematic view showing another embodiment of an electrical circuit according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Please refer to  FIG. 4 ; each bulb assembly ( 3 ) of the present invention includes a shell ( 60 ), a bulb holder ( 61 ), and a bulb ( 33 ). A Zener diode ( 2 ) is placed in a space ( 71 ) in the shell ( 60 ), under the holder ( 61 ), and between the electric wires ( 7 ). Since the space ( 71 ) is so small, any electronic piece received therein must be small and economic that provides utilized value therefore. A bulb ( 31 ) is connected with the bulb holder ( 61 ). 
     As  FIG. 5 , the present invention shows an improvement of a continuous current control circuit module of series string bulbs. The invention includes a power source ( 1 ) and electric wires ( 7 ), which connect with several bulb assemblies ( 3 ) in series. The improvement of the present invention is to connect a Zener diode ( 2 ) with the bulb ( 31 ) in parallel inside the shell ( 60 ). 
     As  FIG. 6 , the present invention is capable of connecting a rectifier ( 4 ) between the output end of the power source ( 1 ) and the input end of the bulb assembly ( 3 ) in case to transfer the AC current into DC current while the bulb ( 31 ) is LED bulb. A resistor ( 5 ) can be provided to stabilize the electric voltage. 
     In actual application, the Zener diode ( 2 ) of the present invention connected with the bulb assembly ( 3 ) provides a completed electric connection of the circuit. When the bulb ( 31 ) is normal, it is nothing at all. But when the bulb ( 31 ) is broken, the Zener diode ( 2 ) will keep the electric circuit in normal and maintains the light string in usual lighting module of decoration.