Design and production of life extender for incandescent bulbs

The circuit working principle of the device is shown in Figure 6. When the power switch S is not turned on, it is grounded. Due to the delay effect of RC, at the beginning, the ③ and ④ pins of the 5S module are high level, the circuit inside the module is turned off, and the relay J is in the released state. Due to the effect of the diode, the voltage across the bulb H is only 0.45 times the rated voltage (220V), that is, 99V. This greatly reduces the surge current generated when the light is turned on due to the low resistance of the cold filament of the bulb, that is, the low-voltage preheating (increasing the resistance of the bulb filament) is achieved. After a period of time, C is charged through R. The voltage of the ③ and ④ pins of 5S is getting lower and lower, and finally the working state of the internal circuit of the module is reversed, the relay is attracted, and its normally open contact is closed, shorting the diode VD, so that the bulb H can work at full voltage (220V). This can extend the service life of the bulb. The delayed opening time of the 5S module is calculated by 1.1RC. Relay J should be AC ​​type. This circuit is suitable for incandescent lamp groups, such as street lamps, corridor lamps, etc.