Graphic WAL-MART 60W-LED bulb interior structure

In October this year, WAL-MART launched a self brand LED lighting product line Great Value, and will soon arrive in the United States in all stores and Walmart.com website, the lowest price of less than $9. The bulb is said to be made by TCP, a Chinese supplier of lamps and lanterns, offering two levels of brightness: 800 lumens equivalent to 60W and 470 lumens equivalent to 40W. Each light bulb is provided with an adjustable or non dimmable version, with a 800 lumens adjustable light price of $9.88 and a dimming version of $8.88. Here is a graphic adjustable light of 800 lumens, equivalent to 60W bulbs.

Light adjustable and non adjustable light side view

Outer packing, it is difficult to distinguish, the only difference is the logo can be adjustable in the non light packaging side of the corner lamp lower figure on the arrow. The adjustable version of the light does not have any logo, which will allow consumers to buy and go home after the supermarket is difficult to distinguish, easy to confuse. Packaging is another example of chaos: in the flexible packaging marking "rated indoor / outdoor closed lamps" (see below), but the above is not difficult to see that the bulb itself can not be used in the logo "lamp completely closed in".

According to WAL-MART, this performance bulb 11W, 800 lumens in the bulb base print logo: consumption 10.5W, through the meter test is 9.3W, the power factor is 0.93. The light from the 2700K version of the "soft white" light bulb is more comfortable and bright.

How to dimming performance bulb? First, through the wall dimmer switch to test its fast running up and down to the level of brightness are good, in a subsequent test, after dimming and switching quite a lot of time, there are some brightness level instability and flashing situation. Light mode bulb and how? The bulb is designed as a sno- cone, the LED chip is arranged in a flat plate, and the light beam is projected as a spotlight or flashlight. This means that the bulb is not all round, like an incandescent lamp, even like an energy-saving lamp. The following figure shows the distribution of light, the bottom of the bulb has obvious black spots. A sno- conical design itself will produce the light energy star requirements for all direction lights should be uniform beam angle more than 270 degrees (+ 135), the WAL-MART bulb plastic cover may explain why sno- is difficult to achieve the design of conical light mode. The shell is made of plastic, and underneath it is aluminum. The plastic cover is not removable, here is cut open, can not be disassembled is a good thing, because most of the LED light bulb is a design of non isolated LED driver, which means that when the housing demolition of AC power supply is exposed, not safe, so WAL-MART this sturdy lamp housing good design. It can be seen that the 38 plastic packaging LED components on a metal core printed circuit board, which is mounted on a circular metal plate. The importance of this metal plate is that it transfers heat from the printed circuit board of the LED to the round metal ferrule, which sends heat to the surrounding air through the bulb base. Please note that this metal base does not have any other LED bulb common fins. The temperature of the metal base is 150 degrees F (about 65 degrees Celsius). The WAL-MART LED is a plastic package, while the CREE and PHILPS LED are packaged in ceramic. Compared with LED, the ceramic package is more heat resistant and aging resistant. Cree's use of ceramic packaging LED may be one of the reasons for its 10 year warranty for light bulbs; WAL-MART offers only a warranty of 3 years.

Is the observation of the light emitting diode array distance shows the LED driver in the bottom of the lamp electronic bulb holder connected with two DC power supply through a conductor on the mounting plate hole, up through the matching of the metallic core circuit board LED array hole. The wires are welded manually to the top of the metal core plate and fixed with glue. This manual welding power cord LED array is typically made in china. However, manual welding is the biggest reason for the problem of LED lights on the statistics, this may be the only reason WAL-MART provides three years warranty.

The drive electronics: the key components of lighting is all power control integrated circuit. Note that the chip has 10 pins on one end, and then the other end of the 2 pin. This gap may be used to isolate the internal circuitry of the IC from the high voltage part of the low voltage.