Dimmable vs non dimmable LED lamps

I've bought some more LED lamps to play with. A bit safer than the last lot, and one of them claims to be dimmable. But is it? Let's put the two new ones to the test and see what makes them tick.
The schematics can be found on my Google+ page.
plus.google.com/b/10694829333...
INDEX
0:00 Index
0:10 Introduction: two "38 watt" LED corn lamps
1:05 Power consumption tests
1:28 Voltage rating tests
1:50 Testing on an ordinary dimmer switch
4:07 Inside the old "bare LED" lamp
4:58 Inside the non-dimmable lamp
5:50 Inside the dimmable lamp
6:38 Conclusion

[@Aspenex]

Great presentation !

[@thdotaku]

Great video, exactly what I wanted to know about dimmable leds and if they are a scam.

[@AintBigAintClever]

Yep, there's definitely a difference between them. Unfortunately there also tends to be a huge difference between the lamp wattage advertised and the true lamp wattage, so there are still scams to be had.

[@andrejrockshox]

so, why the non-dimmable one has a chip? what does it do? also, how come the "old one" can be dimmed, and yet i has the most basic circuit?

[@bunberrier]

Thank you for the tour. After replacing several LED lamps in my house I was interested to see what makes them fail, and suspected a electrolytic drying out. Im going to take one today, a Philips, to work and dissect it.

[@JohnyRalte]

So what is the verdict, my good man?

[@bunberrier]

@@JohnyRalte That particular one was all potted together in a gray lump so I gave up.

[@CTimmerman]

@@bunberrier A gray lump should keep in moisture, but sounds like it also keeps in heat, which also explains why my Blokker LED GU10s died and my cheap Chinese GU10s with vent holes and fewer components did not until breaking their thin plastic shell by accident.

[@kabulkhan5144]

You can Dimm the non-dimmable LED but it will die in one week, per my experience so make sure to buy the dimmable, that would be the right choice to install.

[@madbstard1]

Good to see you back again! Yeah - some of the bulbs (and other electronics) you get on eBay are well "enhanced" in their specs :D If you're doing any more sketches can you change the colour of the tracks - was very hard to see.

[@AintBigAintClever]

Those are the defaults in Eagle. I'll see what I can do next time, although some of the finer tracks can be hard to make out when watching the video in non-HD.

[@madbstard1]

Maybe I should clean my glasses.......it might help lol

[@AintBigAintClever]

I've now posted versions of the schematics on my Google+ page, see what you think. plus.google.com/b/106948293336791915873/+AintBigAintClever/posts/HkGXAXjNJ99

[@madbstard1]

Like day and night :) Cheers for that.

[@dwalden74]

So what exactly makes an LED “dimmable” or not? Is it the circuit board, or are the actual LED chips different? Can you make a non-dimmable LED dimmable by building a different circuit?

[@AintBigAintClever]

It'll be the driver circuit.

[@vovtz]

What type of dimmer were you using, leading or trailing edge cut?

[@AintBigAintClever]

Leading-edge.

[@ashishkp38]

Can I use a dimmer switch on a non dimmable lamp with dimmable leds?

[@NikolaosLedZeppelin]

You can't dim an led lamp with convetional dimmers (V/I). You must use pwm dimmer for an efficient dimming.

[@lisacallipari3190]

Learnt that the hard way, my local electrician didn’t know that and installed them anyway.

[@claudb1029]

Interesting presentation. Based on experience not technical knowledge. Our home is about 5 years old and many of the light circuits have dimmers on them. None of the original ones are labeled for leds. I've replaced most every bulb in the house with LED bulbs most purchased from ebay. The quality is very variable on the ship from China bulbs. The life of the bulb on average is no where near the claim. Sitting on my desk is a pile of 10-15 bulbs all different bases, and styles that have failed in months rather than years. Not at all scientific but it seems the bulbs made in china but with a brand name on them such as GE are far better-not one has failed. As to compatible dimmers. I've replaced some of the non compatible dimmers with compatible dimmers. The advantage of the compatible dimmers is they do not create as much noise in my FM radio. Terms of SAFER, all the LED bulbs I have say for indoor use only. I do have two in an outside pole lamp. The lamp is metal, it is on a beaker and a ground fault interrupter. Been out there for 3 years-so far so good..

[@claudb1029]

I noted another reply about bulbs on dimmers quickly failing if used on a dimmer. Above, I reported a high failure rate. All the bulbs I've bought are stated to be dim-able so that is not the issue. As stated I bought bulbs on ebay. A fact of life. On ebay there is no seller loyalty. It is PRICE,PRICE,PRICE. Had I bought them from a local retail store, like Home Depo, Lowes, Walmart, it would have cost me slightly more and they would have exchanged my PILE of defects.

[@nimeni86]

02:58 - Why didn't the led turn off completely? I'm having the same problem in my car, i swapped all incandescent interior bulbs with LEDs. The LED that's controlled by the doors is dimming but won't turn off completely. I measured 7.2 volts when all doors are closed.

[@DarkLinkAD]

I have the saem issue, in an old house :P

[@HalvardSkurve]

The led lamp uses extremely little current to glow slightly. If there is a little leakage in the sircuit it will glow. To prevent this on a 12V system, put a resistor in parallel with the 12V bulb. A 1/2W 330 ohm should handle 12V, but might get a little hot. You might also try a higher value resistor, to make it run colder, but a to high value will not stop the glowing. You can try 1k also, it might do the trick without getting hot. The same could be done on a higher voltage LED bulb, but then you would have to open the bulb, and put the resistors in parallel with the leds. Also remember to calculate the power consumption of the resistor, making sure it does not get to hot. A higher value, like 10k might do the trick, but that depends on the sircuit and how many LEDs are in series.

[@mehmettakkin2739]

it is soo good

[@CTimmerman]

Some LEDs have a capacitor that takes a while to discharge.

[@rubenortega6476]

Most new LED lights require a ELV (electronic low Voltage) noise reducing dimmer. If you are having issues using dimmers on LED lights save your self a lot of headaches and just purchase a Viribright LED dimmer switch. ELV 300VA 2 way or Single Pole. for like $16 on amazon

[@AintBigAintClever]

ELV isn't Electronic Low Voltage, it's Extra Low Voltage. ELV covers up to 50V RMS AC or 120V ripple-free DC. en.wikipedia.org/wiki/Extra-low_voltage

[@TU154B1]

Bridge in 1st schematic is incorrect

[@cmuller1441]

I think the full bridge rectifier at 4:37 is not properly drawn and is not working properly...

[@AintBigAintClever]

Yep, already spotted a few months ago. I've made a bigger balls-up than that though. Take a look at ALL of the LEDs! :D

[@cmuller1441]

AintBigAintClever I guess we should concentrate on what is right to save time 😅

[@BatEatsMoth]

Do these strobe at all when the power is all the way on?

[@AintBigAintClever]

Not that I've seen. I've got some dimmable LEDs in my Steinel L115 outside lights which gradually fade on and off. No flicker on those.

[@BatEatsMoth]

@@AintBigAintClever I mean the 100/120 Hz flicker associated with LED's with cheap drivers. By strobing I mean a literal strobing effect you get when moving an object in front of a bulb (i.e. waving your hand or a pencil), and that you might be able to see in your peripheral vision as a constant flutter depending on your position relative to the bulb. I'm not talking about an effect you see when reducing the power with a dimmer. I've bought a number of different branded LED bulbs that produced 120 Hz flicker and strobing. The flicker at that speed isn't visible; only the strobing effects. They also made a high pitch whining sound. Supposedly, corn lamps are the worst. But there are mixed opinions on that, probably because some have higher quality parts.

[@zx8401ztv]

It would have been nice if they printed "non dimmable" on the bulb, daft manufacturers lol. Your first diagram looks wrong on the bridge rectifier, it wont work like it is, spin the bridge anticlockwise 90 degrees :-)

[@AintBigAintClever]

Dammit, that's why I prefer all-in-one bridge rectifiers, easier to draw :D

[@AintBigAintClever]

Corrected version of the image on Google+

[@zx8401ztv]

LOL draw an oblong and put + - and ~ ~ on it :-D. Some things just dont go into memory too easy, pnp transistors have allways been hard to cope with, its backwards logic for my grey squidgy thing between the ears :~). Its like positive earth cars, the brain just cant cope lol.

[@AintBigAintClever]

I've just realised that I've made a bigger cockup on those schematics. Can you see why NONE of them will illuminate? :D

[@JoshKaufmanstuff]

Reversed Polarity on the LED arrays?

[@ifell3]

Great video, you have no flicker,,,, I take it your video settings are 25 or 50 FPS,,,, would a dimmable led still flicker at UK 60hz video FPS at 30? Regards

[@AintBigAintClever]

Yes, recorded at 1080/50p then dropped to 1080/25p for editing. Now you've mentioned it I've done a quick Google and if my camera is in 1080/50i mode but with "Digital Cinema" enabled, what's laid down is 1080/25p. Flicker would be less noticeable at 60/30 than 50/25 but what you may still see on recorded footage is slow-moving banding if the camera and lamp aren't at a perfectly-matched rate (e.g. 60.01Hz power and a 60Hz recorder)

[@TomCee53]

@@AintBigAintClever more likely the other way. The power companies are very particular about frequency. Something about clocks counting the cycles 🤪

[@AintBigAintClever]

@@TomCee53 It took me a few goes re-reading my comment to see (1) what I was going on about, then (2) what you were going on about :) That's very true, mains frequency should be locked at 50Hz, and clock sync is something you take for granted until you replace your old mains-powered alarm clock with a USB-powered one and find it runs slow. Funnily enough Tom Scott has done a video about mains frequency and the fact the European one drifted away from that of the UK. kzbin.info/www/bejne/mJrNXn2gr6iUbdE

[@skbakanov]

Plus hey! If I’m putting a 38w lamp that’s brighter then 100w inc. lamp while satisfied with output and only draw 16w, better yet. Rather claiming 16w but using 38w!

[@AintBigAintClever]

I'd be more satisfied with getting the output I'm paying for, but measuring total light output from a lamp would involve surrounding it by one big light meter, and that's going to be expensive.

[@skbakanov]

AintBigAintClever you don’t need to surround it with anything. Take a known light source as a controlled and set up a simple light meter at both lights at same distance. Far enough where light is defused somewhat

[@skbakanov]

Reason you don’t read the full wattage rated, is you have a lamp that is rated 90v - 280v or so. So the wattage claimed is at 280v. Don’t judge the bulb by its wattage. Judge it in lumens. Wall heater is 1000wats and don’t putout shit for light. Just a thought.

[@AintBigAintClever]

So it would be acceptable for these to barely illuminate if you're a US customer running them on 120 volts?

[@skbakanov]

AintBigAintClever I know it’s isn’t a resistive load but rather pwm driven. What I meant to say is the consumption varies on buck boosting or boosting input voltage. Some goes in heat etc. Also heat. Heat will draw more amp right? For instance, an led at 3.5v will consume 3 w but at 3.8 v 7.6w Let them go up to normal operating temperature and then measure the wattage.

[@AintBigAintClever]

@@skbakanov I think the ones of mine which aren't currently in active service (because I've replaced them with better ones and they're too fucking dangerous for open fittings) are capacitive droppers rated 220-240V, but those actually had the claimed output voltage. I'll have to see if there's one knocking about that I can test across a wider voltage range, although then I'll have to use a dual-multimeter setup because I don't think my plug-in meter will run if I drop the voltage too far down, and I can't use it on the input to the variac as the variac will be drawing power as well. Have you checked out bigclivedotcom's videos? He's played with far, far more LED lamps than I have. Julian Ilett has done a few, too.

[@skbakanov]

AintBigAintClever thank you for your humble and humbling responses.

[@AintBigAintClever]

@@skbakanov You mean last night's snappy-but-tired and today's more reasonable responses :)

[@MyProjectBoxChannel]

Dim it with a capacitor 😉 kzbin.info/www/bejne/gHmZaap4jbRooJI

[@jusb1066]

i thought you had gone! of course teresa may could have nuked Wales, its not like murdoch press would have reported it

[@AintBigAintClever]

Fuck don't give her ideas!