Light string without using a control box

A light string without using a control box, comprising:

• a plug receiving an AC voltage and having a first voltage converting circuit;
• a tail socket having a second voltage converting circuit, wherein the first voltage converting circuit and the second voltage converting circuit commonly form a power converting circuit to convert the AC voltage to DC voltage;
• multiple LED lamps electrically connected between the plug and the tail socket and including a primary LED lamp and multiple secondary LED lamps, wherein
• the primary LED lamp has
• a primary control chip having a data output terminal and outputting control data;
• and
• a secondary control chip having a data input terminal connected to the data output terminal of the primary control chip and a data output terminal;
• and
• each of the secondary LED lamps has
• a secondary control chip having a data input terminal connected to the data output terminal of a previous secondary control chip, whereby all the secondary control chips and the primary control chip are connected in sequence;
• multiple wires connected to the plug, the tail socket and the LED lamps and only consisting of
• a first AC wire and a second AC wire connected between the plug and the tail socket for transmitting the AC voltage from the plug to the tail socket;
• a DC wire connected between the plug and the tail socket and electrically connected to each LED lamp to provide the DC voltage;
• and
• a signal wire connected to the LED lamps in series to transmit the control data from the primary LED lamp to other secondary LED lamps so as to control the LED lamps to produce variable effects according to the control data.