All the lights (100pcs) are connected in series. Once the flashing of the light fails or is lost, the NTC thermistor gradually self-heats under the action of the current. As the temperature rises, the resistance of the NTC thermistor gradually decreases to only one tenth of the original resistance is stabilized. So the entire string of lights continue to work. Since the resistance of the thermistor under the operating current of the circuit is opposite to the resistance of each of the lights when operating, the entire circuit current will not increase. The current design is prevented from increasing the current caused by the copper oxide wire and causing the residual light to gradually increase the current and continuously fail.
Open circuit protection with NTC thermistor, the advantages are low cost and high reliability. We have experimented and used the NTC thermistor's Christmas light string to work continuously for 3 years without any problems. In general, the NTC thermistor used in the light is a glass-sealed NTC thermistor. Because it is packaged in a glass, it can be used in harsh environments such as high temperature and high humidity. It is small size, light weight and strong structure make it easy for automatic installation.
The principle of flashing lights: turned on the power, due to the two pieces of metal in the neon bulb are not connected, the power supply breaks through the xenon conduction (the breakdown voltage of the small bubble is about 15-25V). Then we can see the bubble light When the helium gas is electrically conductive, the bimetal in the bubble (that is, the one we see bent) is reduced in curvature after being heated, and the two electrodes are turned on at the same time. Since the helium in the bubble is no longer conductive after the bimetal is turned on, the temperature drops rapidly, the bimetal returns to its original state, and the power is quickly cut off. Repeatedly, the lights are constantly on and off and flashing.