Production of an LED lighting lamp

Before making it, first have a general understanding of the characteristics of white light LED. This kit uses a straw hat head white light LED with a diameter of 5mm. Each LED has a rated voltage of 3.0~3.2V, a brightness of 1400~1600mcd, and a rated working current of 20mA. When the working current is smaller, the luminous efficiency is higher, the temperature rise is lower, and its effective light source life can be more than 20,000 hours. (Because as the use time increases, the brightness of the LED will gradually decrease due to light decay. The effective light source life refers to the cumulative working time that the LED can emit effective and useful light when it is working. Beyond this time, although the LED can still light up, the brightness is too low, thus losing its practical value.) The service life of ordinary energy-saving lamps is only about 5,000 hours, and the life of ordinary incandescent bulbs is only about 1,000 hours. From the cost of replacing bulbs and the electricity bills saved, using LED lighting is still very cost-effective.

The actual power consumption of the whole lamp is about 3.3W. After lighting, it is roughly equivalent to the brightness of a 40W incandescent lamp, which is equivalent to the brightness of a 7-9W energy-saving lamp. When it is lit for 24 hours continuously, the power consumption is less than 0.08 degrees, which has a significant energy-saving effect. The bottom of the lamp adopts the E27 specification threaded port consistent with ordinary incandescent lamps, which is easy to install. The frosted lampshade ensures a high light transmittance while also preventing glare when looking directly at the LED. This LED lamp is suitable for use as lighting in small areas such as desks, bedside tables, kitchens, bathrooms, public corridors, etc.

The circuit schematic is shown below. The 220V mains power first passes through C1 and R2 to reduce the voltage, where R2 is a bleeder resistor and C1 is a voltage-reducing capacitor with a withstand voltage of 400V. After that, it outputs direct current through the W1 rectifier bridge, and then after current limiting by R4, it is sent to 60 LEDs connected in series. Because the load of the LED connected by the resistor-capacitor voltage reduction is not a pure resistor, but a voltage regulator tube characteristic, the components are selected according to the parameters of this schematic diagram, and the current flowing through the LED is about 13mA. C2 is a filter capacitor, which can prevent the impact of high current on the LED when the light is turned on. R1 is an NTC thermistor. When an unexpected situation occurs in the circuit and causes the current to increase, its resistance value becomes larger, causing the current to decrease, thereby playing a protective role.

The LEDs are equipped with 60+2 pieces, 2 of which are spare parts. The component surface of the circular printed board with LEDs is painted with white paint to increase the reflective effect. To facilitate user production, the 220V lead wire inside the threaded port has been crimped with a special tool when the kit leaves the factory, which can prevent the lead wire from falling off and causing accidents.

Now let's start assembling. You can solder the LED light board first. The long pin of the LED is the positive pole, and the short pin is the negative pole. The shadowed end of the LED symbol on the circular printed board is the negative pole. Because LED is a highly sensitive electronic component with low voltage and low current, white light LED is very sensitive to static electricity. If it is damaged by static electricity, it will show some bad characteristics, such as increased leakage current, no light or abnormal light emission during testing. Therefore, anti-static protection must be done during welding. The operator should wear an anti-static wristband to prevent static electricity from damaging the LED. Use a 30W pointed electric soldering iron with no leakage to weld. You can first solder one pin of the LED and observe the position of the LED. If it is not correct, you can straighten it when the solder melts. After confirming the correct position, solder the other pin. Welding should be quick and decisive, and the welding time should not be too long. It should be controlled within 2 seconds, otherwise the LED may be damaged. Solder the LED on the circular printed board one by one according to the symbols.

Next, solder the driver board. Refer to the component numbers in the schematic diagram and solder the components one by one on the driver board.

Then use wires to connect the screw mouth, driver board, and LED light board. Connect the middle point lead of the screw mouth to C1 of the driver board, and the lead of the threaded part to R1. The output "+" and "-" of the driver board are connected to the "+" and "-" of the LED light board respectively. Note: The output lead of the driver board must first pass through the fixing frame and then connect to the LED light board.

Install the driver board into the lamp body, and use a hot melt glue gun to fix the four corners of the driver board to the lamp body. If you don't have a hot melt glue gun, you can cut the glue block in the kit into four small pieces with a knife, and use a soldering iron to heat the glue block to fix the driver board. Then install the fixing frame into the lamp body, and rotate the fixing frame along the groove in the lamp body so that the four wings of the fixing frame fit into the groove.

Use screws to pass through the middle hole of the LED light board and fasten it to the fixing bracket.

Finally, put on the frosted lampshade and the LED is ready.

Install the assembled LED lamp on an ordinary screw lamp holder, and you can enjoy the different experience brought by the new lamp that is both energy-saving and environmentally friendly.

Tip: Screw-type lamp holders with dimming function, voice control, and other thyristor control are not suitable for direct installation of this LED lamp.