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Sengled smart light bulbs Teardown

Wi-Fi- and app-connected peripherals are becoming very popular. All kinds of products are hooked up via Wi-Fi to our smart devices. For example, we have already done teardowns on products such as a Wi-Fi-connected bulbs from xiaomi yeelight. In this Teardown, we are going to take a look at a Wi-Fi-enabled light bulb from Sengled Smart Bulbs.

I think the one selling in US and In China Mainland is different. In China, it is a WI-FI LED bulb. But the US version is Zigbee, only 10 USD. If you are interested in this, go to the website,  Sales On, Sale on

The Wifi Bulb is 59 RMB, 8.5 USD. The Sengled E11-G13W Smart LED Soft White (Element Classic) Bulb  in the US is 9.9 USD. Oh baby, i do not like this, it seems they disrespect the USER from China?

Part Number W11-C21(huawei), US name E11-G13W
Item Weight 120 g
Product Dimensions 61.5 x 115 mm (A60), US: A19
Item model number 生迪智能LED 球泡灯
Size 1 Pack Bulb
Color Soft White
Material Plastic
CCT 2700 K
Lamp Fitting E27, US : E26
Power Source AC
Beam Angle 240 degree
Voltage 220 -240  volts
Wattage 8.6 watts
Power Factor 0.7
Comm  2.4 Ghz WI-F, IEEE 802.11 B/G/N
Item Package Quantity 1
Type of Bulb LED
Luminous Flux 806 lm
Certification CQC, gb 24906-201, gb 17625,  gb/t 17743-2007 (US :ENERGY STAR, UL)
Special Features Dimmable, Easy to Install
Usage Commercial/Residential
Included Components Element Classic Bulb, Quick Start Guide, Product Information
Batteries Included? No
Batteries Required? No
Warranty Description 3 Year
System IOS 8.0,Android 4.1

1, Package

Here are package, all Chinese, you can find Technical Details. Not nice as the US Version.


Below is US Version with zigbee.

Sengled Smart LED Soft White-Element-packClassic

2, Testing

Here are some testing data with this smart light bulb. The flicker is obvious, if you take a picture.

2.1 Input power Testing

Testing power is 7.8 W, after half and hour at 226.3 W, PF> 0.8. it is good. And what is the standby power, 1 W, PF 0.5.



2.2 Lighting output Testing

Next is lighting spectrum, testing in midnight, the CCT is 2789, SDCM is 2.9, also good testing data. R9 is 14.



2.3 Flicker Testing

The LED output then correlates with the output waveform of the driver. Power correction components within the circuit must also be fixed. Without this, ripple currents(check below wave) in the power flow will cause flickering. LED flickering can be tied back to the driver component within the lamp. The essential purpose of the LED driver design is to rely on a simple circuit to control output current(or AC TO DC), but without altering the frequency, the LED becomes likely to show visible flicker. However, this can be fixed by using constant current drivers, which remove the peaks of the sine wave.

Flicker by handy equ. Dimming via the APP, at different power. The flicker is 25.6 % at full power.


The flicker is 9.6 % at 45 % power. you can find the lighting current form below chart.


The flicker is 9.6 % at 19 % power. you can find the lighting current form below chart. it also is straight line. 



2.4 Thermal Testing

The amount of light from the light source at a specific time in the future is referred to as the lamp lumen maintenance factor, or LLMF. The lifetime of a LED module is defined as the time it takes until its light output, or lumen maintenance, reaches 70% of the initial output. This is also called L70.

The module does not die instantly as many conventional light sources do, it slowly dims down, with high temperature, it will run fast. In fact, manufacture has the LM80 report. So when design the LED bulb, they have to take caret this.

Conduct the thermal test on the housing part, the higher is about 65 C, @25 C ambient environment.


led chip testing, the chip is higher as 115 C, of course, put in the Cover. Oh my baby. I am not like this one, as the led chip lived in the close environment, it is too bad for the product life.


3 Software Part

It is easy to use, but quite simple APP, testing on Android only. Below is the connecting process, UI. Not like the US version, it can work with Echo. This one can also be controlled by Voice from HUAWEI Speaker. There is another version, work with Tmall Speaker.  For End user, it is quite mess.





4 Teardown Part


I just tear down the CN version, but i am also curious the one selling in the NA. If you know that, pls comment. US version with zigbee, CN with Wifi tech.


This was probably the easiest teardown yet! Opening this light bulb was super easy. The plastic diffuser dome was simply pulled off to reveal a circuit board mounted with two Phillips head screws. Antenna is in your face, it is trend nowdays.

You  can see differents parts of LED Bulb, it take some time to dissemble. It is full of White potting.

LED Board, total 16 2835 LED chip, 8S2P. The LED Board PCB is from JIANGSU DIFEIDA ELECTRONICS CO LTD, item no DFD-8, V-0 , 38 mm OD, 1.3mm thin. Link:


19 Big Components inside, so it is quite not easy to build inside. Especially with WIFI module. LED Driver PCB E157952, link:

I just see electrolytic caps and immediately start thinking about lifetime issues. what is the lifetime? 25 k for thw whole lamp??? Are you kidding me? Engineer.  All the E-cap in the main Power supply is 105 C, the one in the wifi module is 130 C. LOL, that is funny.


LED Driver Chip U3, on the back of Power Supply module. The MT7860(Maxic Technology, China) is a high power factor (PF) Buck. LED Driver. It works under Quasi-Resonant. The file here: f ,MT7860), or this link :


LED Driver Chip U2, LYT0004D, from Power Integrations, Lowest Component Count, Off-Line Switcher IC for Non-Isolated LED Lighting Applications . datasheet:


BR, MB6S, from ON Semiconductor / Fairchild . The MB family of bridge rectifiers is a 0.5 A, 600 Vac rectifier family that achieves high surge current absorption within a very small foot print


DGS, SVF2N60V(2A, 600 V, N-Channel), from Hangzhou Silan Microelectronics, only $0.2  per pcs. link:


Wifi Module, from mxchip, Item no. EMW3090-P. Embedded WIFI module RF Exposure details,  made by Shanghai MXCHIP Information Technology Co.,Ltd.





The Bulb demonstrates how  components are needed to get any device connected to the internet in some fashion. I am not an engineer to circuit. So it is hard to me to understand the circuit/RF/.

I am not interested in this bulb, as the bulb flicker is bad, and I am not saying the bulb in the US is better, but i would like to buy this one.

Here is the use at home.




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