Philips' new LED light bulbs are brighter, more efficient, not cheap

How do LED household bulbs work?

I came across some in a friends house the other week and they were awful; almost like being in a strobe effect disco from the 1970's. God help anyone with epilepsy. This is why I ask the question above.

In my basic understanding of LED's on an AC household system, they'll be switching on and off at 30 times a second in the US but only 25 times a second here in Europe . A CFL bulb will be flickering on and off at 60/50 times a second and the traditional old incandescent will be the same, but glowing hot and thus have no perceptible flicker.

So are there designs of LED's that stop this strobing flicker? I can see significant issues if there aren't.

 

Yes it's same one I had except lasted 1-yr not 22.8 years.
They are guaranteed for 7 years so I should be able to get replacement.
But I thought I was going to have this bulb forever...I got 3 so far -1 dead.

 

For both LEDs and CFLs, any 'slow' flicker should be at 120 times per second in the US, 100 times per second in Europe (one blink each half cycle of the AC mains). I cannot see it in stationary situations, but know people who can. Anything slower indicates something broken in the rectifier or controller.

Faster flicker frequencies may also be present.

 

You sure? I'm sure the ac mains swaps 50 times a second, making an LED switch on every alternate time, making a 25 times a second flicker (or 30 in the US). How else does it produce that slight flicker similar to an old movie projector?

Or are they cheap LED bulbs only using one half of the phase rather than wired in for both? Or should they have a separate controller built in that flickers at a certain amount whatever the frequency of the ac mains power? But it was definitely noticeable if you moved your hand quickly infront of the bulbs.

 

Yes, I'm sure. Your AC mains reverses every half cycle, or twice per whole cycle. With 50 whole cycles per second, that makes 100 half cycles, or 100 reversals, per second.

With a full wave rectifier, light should pulse every half cycle. A half wave rectifier (either intentional, or a partially broken full wave configuration) will cut the pulse rate in half. Too-cheap devices might go the half wave style, but in large quantities it will raise havoc with the transformers between your house and the generators.

Good controllers can both reduce the flicker amplitude, and boost the flicker rate to rates above human perception. It just takes money, which is why consumers don't like the better products.

 

It's easy to imagine the cheap LED bulbs giving a misleading impression of what to expect.

Quality has improved so much over the years, the nice ones have become undetectable.

 

We have replaced ALL the CFLs in our house, with LEDs, cutting our energy consumption by about 1/3, down to 1/10 since changing from conentional bulbs. Quality of light is fine.

Icarus

 

So it sounds like my friend has purchased cheap ones from China? Knowing him, that sounds about right.

I guess if I bought a genuine Philips bulb it'll be fine, but they're still way expensive over here.

 

The Philips LED bulb features incredible simulation of 60-watt incandescent in terms of light qulaity and light distribution. I try to get em for <~$16 per bulb after Philips rebate. But there are some cheaper high quality LED bulbs, they just are more directional light beam, which is better for some applics.

 

Just did a UK search and found the following;

Philips LED GLS Lamp | LEDBulbs.co.uk

I want one to replace the old 60w bulbs. That website is as clear as mud. Do I bother or do I just get a 40w halogen (same output as the old 60w's) for £1.50?

 

No problems with flicker of the LED already installed in my house.
Early designs did have a issue with flicker, so I returned them and got my money back. As, already mentioned the newer designed LED lights have overcome the issue of flicker.

DBCassidy

 

Wow that is incredible selection of LED bulbs from Philips I do not think that all of those are on the market here.
The bulbs we are talking about are the funky yellow ones near the bottom (12Watt Dimmable ES/E27). You are showing $L28 we were $25 last year now down to $21. Here in USA Philips has $10 rebates on purchase over $30 so I would get 2 bulbs and then get a rebate. For these bulbs I tend go to EBay to get cheapest price and free shipping. Looks like you just have 3 yr warranty we have 7 yr (22.8 yr life calculated by an over-accurate engineer). I had thought it made sense if I kept the bulbs my whole life and willed them to my kids. Good as gold, but now that one bulb died on me, I realize 22.8 yrs life does not make sense for any electronic gizmo. 3-yr warranty does not guarantee payback to you.

 

... so I called Philips and they said sorry about that dead bulb, reimbursement check in the mail.
I will probably roll it over to two more new bulbs, since price is lower this year.
Unlcear to me if they had a record of my purchase from the rebate offer.

PS- Philips cust. service guy said be sure to recycle old LED bulb properly and he suggested take it to Home Depot. Wonder why? The one thing I notice is the bottom contact appears to be lead solder versus some LED bulbs seem to have a shiney metal contact.

 

ya that is right. it will be a multiple of 60 and 60 hz is simply too irritating to be marketable. the LED is not an incandescent so it runs on DC which has to be "made" 120 is an option but 240 is possible and so on.