It's a while since I've taken a small Chinese LED lamp to bits. This one was randomly added to an ebay order from China and came in a box with a matching lamp free. I'm not sure it was supposed to be free, they may not realise there are two in each box.
The lamp has a single round circuit board with nine 5730 (5.7mm by 3mm) single chip LEDs on the front and a typical smoothed capacitive dropper on the back.
The series capacitor is a whopping 820nF and after rectification it is smoothed by a 400V 4.7uF electrolytic capacitor before driving the LEDs via a rather lightweight 1.5 ohm resistor.
I measured the current through the circuit by simply bridging one of the LEDs with a meter while the power was on (yes, live exposed solder connections again) and measured 50mA which means the lamps rating is roughly 1,5W. The listing said 3W but they often do. And to be fair they sent two 1.5W lamps which adds up to 3W....
Both the series cap and smoothing cap have 1.1 Megohm resistors across them for discharging when the power is turned off.
Pretty much a typical cheap LED lamp. Very simple and works. The quality of the LEDs may be a bit suspect as I tested them with a very current limited supply and they had the characteristic of a crappy doomed-to-failure LED. With one light one of the LEDs didn't light until it had been running for a while and "blew clear". On the other there was a dim LED. With both, when the wall switch is off the slight capacitive leakage through mains wiring causes the LEDs to glow slightly, but not all of them, even though they are in series.
The lamp has a single round circuit board with nine 5730 (5.7mm by 3mm) single chip LEDs on the front and a typical smoothed capacitive dropper on the back.
The series capacitor is a whopping 820nF and after rectification it is smoothed by a 400V 4.7uF electrolytic capacitor before driving the LEDs via a rather lightweight 1.5 ohm resistor.
I measured the current through the circuit by simply bridging one of the LEDs with a meter while the power was on (yes, live exposed solder connections again) and measured 50mA which means the lamps rating is roughly 1,5W. The listing said 3W but they often do. And to be fair they sent two 1.5W lamps which adds up to 3W....
Both the series cap and smoothing cap have 1.1 Megohm resistors across them for discharging when the power is turned off.
Pretty much a typical cheap LED lamp. Very simple and works. The quality of the LEDs may be a bit suspect as I tested them with a very current limited supply and they had the characteristic of a crappy doomed-to-failure LED. With one light one of the LEDs didn't light until it had been running for a while and "blew clear". On the other there was a dim LED. With both, when the wall switch is off the slight capacitive leakage through mains wiring causes the LEDs to glow slightly, but not all of them, even though they are in series.
1 decades of videos and still amazing videos to watch ๐ good electronics memories
Beware Google translation incoming
I know, old video, but I'm too curious (or too dumb). You mentioned in that video and many others that there really is no contradiction between the mains and the person touching the LED's . But you also said there is 3 volts across one LED. So if I touch the front do I get a full 240 volt shock or does it depend on how many of the terminals I touch, or between specific terminals?
In the EU evryting is tested before it Can be sold
How would a Chinese manufacturer modify this design to make it "Safe" TM? I gather the main issue is the wire-on top going into the LED directly connects to the end that goes into the outlet. So if you weren't grounded and touched it, you'd have a chance of being shocked or jolted. It I presume wouldn't kill you but sting like a bugger. So what would you need to do to resolve this? Coat the metal open connection in a piece of non-conducting rubber/plastic/something like that which is heat resistant?
Big Clive does the UK have something like. U L ,that checks out anything electrical to make sure its safe ,like our products of that type will have a U L seal on the box .I don't no if the U L seal on stuff direct from China ,I need to check .but I guess sometime we have to watch out for,ourselves, or if we our very lucky ,we have your reviews ,to help us and your reviews do help us ,except when their is a country difference, like 110 volt versus 220 volt,I think the 220/volt system is better,that why we use it on things like air conditioners.
i have no difficulty seeing all the details in 480p perhaps i can try 720p but my opendott tab become laggy that way , 8" screen , still no difficulty to see the details. โบ
Clive got an haircut!
+bigclivedotcom
What do you think of your little microscope?
I've bought cheap chinese led automotive bulbs thinking they were a steal when they usually turn out to be garbage. I had led bulbs that were white and turned brown at the diodes from heat, and damaged the light housing. Others function when they feel like it, and keep flickering.
If any of that LEDs would fail then the elctrolitic would explode. Lame design.
A+++++
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