Flicker light string suitable for unlimited series-connection

A flicker light string suitable for unlimited series-connection, each light string including a driver and a plurality of series-connected lamps. The driver has an input end connected to an independent external power supply and a trigger circuit. The trigger circuit has an output end connected to the series-connected lamps and a trigger end reserved for connection to an external cord for acquiring an oscillatory signal to control the continuity and interruption of the trigger circuit, so that the light string can flicker with the oscillatory signal. Multiple units of the flicker light string can be serially connected to form an unlimited extending flicker light string, and all the connected light strings can flicker synchronously without the risk of being overloaded or overheated.

BACKGROUND OF THE INVENTION 
The present invention relates to an improved flicker light string, and more 
particularly to a flicker light string which can be extended in an 
unlimited length by serial connection with other similar light strings, so 
that all the connected light strings can flicker synchronously without the 
risk of being overloaded and overheated. 
Conventional flicker light strings are frequently used as a decoration in 
festivities, commercial advertisements, and on many special occasions. 
Such conventional light strings each can have only limited numbers of 
lamps because of the limited amperage of wires for the light string. To 
extend the length of the light string by connecting too many lamps to the 
wire of the light string shall cause the wire to be overloaded and 
overheated and even cause the lamp's to be burned out. To solve this 
problem, it is a common practice to use multiple separate light strings to 
complete the decoration. The drawback of this solution is that not all the 
light strings can flicker synchronously. To overcome this problem, some of 
the manufacturers/customers ignore the wire load and arbitrarily extend 
the light strings to use the same at the risk of public safety while 
others use larger wires and increase the output of controllers for the 
light strings. The larger wires and high output controllers significantly 
increase the manufacturing cost of the light strings. For example, the 
price for an electronic device of 500 A is much higher than that for an 
device of 5 A. And, even with these dangerous and costly means, the light 
strings still have limitation in their length and cannot be unlimitedly 
extended. In addition, it is difficult and inconvenient in the repair, 
maintenance, and installation of such extended light strings. 
The inventor has developed a flicker light string suitable for 
series-connection to eliminate the drawbacks existed in the conventional 
flicker light strings. 
SUMMARY OF THE INVENTION 
A primary object of the present invention is to provide a flicker light 
string in which multiple units can be serially connected to unlimitedly 
extend the string length without the risk of overload. 
Another object of the present invention is to provide a flicker light 
string suitable for series-connection wherein an output end of the driver 
of the light string can be changed as desired to adapt to either a 
two-wire or a three-wire light string. 
To achieve the above objects, the flicker light string according to the 
present invention includes a plurality of series-connected lamps and a 
driver. The flicker light string so formed has an independent external 
power supply connected to an input end of the controller. The driver has a 
trigger circuit inside it. An output end of the circuit is connected to 
the series-connected lamps and a trigger end thereof is reserved for 
acquiring outcoming oscillatory signals for controlling the continuity and 
interruption of the trigger circuit, whereby the light string can flicker 
with the signals. By this way, multiple flicker light strings of the 
present invention can be serially connected as required without limitation 
in the length of the connected light strings. All the serially connected 
flicker light strings can flicker synchronously without the risk of 
overloading and overheating.

DETAILED DESCRIPTION OF THE PREFERRED EMOB0DIMENT 
Please refer to FIGS. 1A, 1B and 2. The present invention relates to a 
flicker light string 1 including a plurality of series-connected lamps 11 
and a driver 12. 
The lamp 11 each is fixedly connected to a lampholder 111 having a diode. 
The lampholder 111 is then connected to two wires. 
The driver 12 has a trigger circuit inside it. The trigger circuit is 
formed with a single TRIAC transistor 124 and other resistances and 
capacitances. A power input end 121 of the sub-driver is provided with a 
plug 125 for connecting with an external power source. An output end 122 
of the driver 12 is connected to one end of the series-connected lamps 11 
while the other end of the lamps 11 are connected to a common ground end 
128. A trigger end 123 of the circuit is reserved for connection to an 
external wire for acquiring an oscillatory signal to control the 
continuity and interruption of the trigger circuit. The trigger- end 123 
is reserved by providing a copper piercing means on the driver 12, so that 
the driver 12 can be directly assembled to a conductor containing the 
oscillatory signal. 
With the above arrangements, each flicker light string of the present 
invention has an independent external power supply and a trigger end 123 
to acquire an oscillatory signal, causing the lamps 11 on the string to 
flash synchronously with the oscillating signal. 
Please refer to FIGS. 3 and 4 for the series-connection of multiple flicker 
light strings 1. To do so, first connect the trigger end 123 of a first 
flash light string 1 to a main driver 2 containing an oscillatory signal. 
Use the copper piercing means to pierce through an signal cord which 
extends from an output end 222 of the main driver 2 and contains the 
oscillatory signal. The signal cord is connected into the trigger circuit 
of the driver 12 so that the TRIAC transistor 124 thereof is electrically 
connected at the same time the oscillatory signal is received, causing the 
lamps 11 on the light string 1 to flicker synchronously. Since the 
oscillatory signal from the main driver 2 is led into the light string 1 
simply to trigger the lamps 11 without increasing the load of the string 
1, and since every subsequent light strings 1 either series connected to 
the first light string 1 or parallel connected to the main driver 2, all 
have their own independent external power supply, each of the light 
strings 1 has a load current that is used by the light string 1 itself 
instead of a total current used by all the series-connected light strings 
1. Thus, no overload will occur in any of the individual light string 1 no 
matter how many units of the light string 1 are series or parallel 
connected. 
Please refer to FIG. 5 now. In the event a three-wire output end is 
required in the present invention, it can be achieved by a series-parallel 
connection of two diodes 126 and 127 to a signal cord at the output end 
122. With this simple change, the present invention can be more widely 
used either as a two-wire or as a three-wire light string 1 without the 
confusion of unmatched specification to prevent required wire connection. 
From the above description, it can be seen that unlimited units of the 
flicker light string 1 of the present invention can be serially connected 
without any technical difficulty while all the connected flicker light 
strings can be lighted synchronously. In addition, following advantages 
are found in the present invention: 
1. The light strings of the present invention are uniform in their 
specification and are therefore suitable for mass production. Since 
different units of the flicker light string can still flicker 
synchronously, it is not necessary to manufacture light strings in 
different or special specifications. The light strings in uniform 
specification may largely reduce the manufacturing cost and allow 
consumers to purchase and use them depending on their actual need. 
2. The products of such light strings are safer in use and cheaper in 
price. The simplified specification of the light string also largely 
reduces the cost for electronic devices thereof and further ensures high 
safety of the light strings in use. 
3. Unlimited numbers of light strings can be serially connected for them to 
flicker at the same time. Theoretically, since each light string has its 
own independent power supply, its operation is independent of the total 
power consumption of the whole connected light strings and of the gauge of 
wires. Thus, unlimited numbers of such light strings can be serially 
connected. It is surely a revolutionary invention in the industrial field. 
4. It is very convenient to install the light strings. Every light strings 
other than the main light string can use the power of a lamp at any 
position after the driver of a preceding light string as its control 
signal. The light strings can be easily connected to form different 
patterns and the assembly and installation thereof is convenient. 
5. The repair and maintenance of the light string is simple and convenient. 
A consumer needs only to replace a complete set of failed light string 
with a new one without the help of any professional electrician. The 
maintenance costs to be undertaken by the manufacturers and the consumers 
are both reduced. 
In brief, the flicker light string according to the present invention has 
simple structure which not only allows mass production to reduce the 
manufacturing cost but also ensures safety in use and lower maintenance 
cost. That is, the flicker light string of the present invention provides 
new and special functions and significantly increases the economical 
benefit of the flicker light strings. 
Although the present invention has been described with the preferred 
embodiments thereof, it should be noted that the present invention is not 
limited to such embodiments and various changes can be made without 
departing from the spirit of the present invention or the scope of the 
subjoined claims.