Patent ID: 9204502
Filing Date: 2015-12-01
Classification: H05B,Y02B

Abstract:
1. A light string, comprising: a plurality of lights connected in series to form a light series branch; and a protecting circuit connected between the light series branch and an AC power supply, the protecting circuit comprising: a diode bridge rectifier configured for converting an AC current from the AC power supply to a DC current, a positive output of the diode bridge rectifier connecting with an end of the light series branch via a first resistor, and a negative output of the diode bridge rectifier being grounded; a line switch connected in series with the light series branch, with a control terminal connected with a connection point between the first resistor and the light series branch via a second resistor; a sample circuit comprising a third resistor and a fourth resistor connected with the third resistor, configured for sampling a line current flowing in the light series branch and outputting a sample voltage, the fourth resistor connecting in series with the light series branch, a terminal of the third resistor being connected with a higher voltage terminal of the fourth resistor, the other terminal of the third resistor acting as an output terminal of the sample circuit, and the other end of a series circuit composed of the light series branch, the line switch and the fourth resistor being grounded; and a control circuit configured for switching off the line switch when the sample voltage is larger than or equal to a preset voltage, and comprising an output terminal for receiving power from the diode bridge rectifier via the first resistor and the second resistor and realizing an on-off control of the line switch; wherein each light is such configured that when a lamp of the light is removed from the light or the lamp is burned out, the remainder lamps in the light string can still illuminate, and a voltage drop across each remainder lamp become higher than before.