Touch Lamp

[pinnerite]

The only incandescent lamp in my house is in a bedside lamp. I tried an LED lamp but it wouldn't dim.

Are there solutions?

[Theo]

You can get dimmable LED lamps - most LED lamps aren't dimmable unless they are advertised as such. How well it works depends on the nature of the dimming method - sometimes they can be a bit fussy and/or flickery.

Theo

[Martin Brown]

Only total replacement of the unit or continue to use a filament bulb.

Problem is that even a dimmable LED bulb requires exactly the right sort of controller and the easy default design of the old days won't work. My friend has had a lot of trouble with officially correct dimmers and LED fighting each other with each manufacturer blaming the other. He's had an endless stream of them fail and replaced FOC under warrantee.

One interesting aside we had a very odd mains failure in our village which is normally powered by two phases into a transformer and one went down completely. The remaining phase found itself doing all the work but didn't trip out so our local mains dropped to around 100v.

Incandescent bulbs were dim and orange but all the LED bulbs were working normally at full brightness. Anything that took real power made the voltage go even lower. Putting the 3kW kettle on resulted in the real time display showing 500W it did eventually boil though!

Northern Powergrid actually did a good job for once. They reset the faulty breaker within about 15 minutes of me calling it in.

[Jeff Layman]

That's interesting. Many SMPSs are designed to work from 100 - 240V. Is it possible that some LEDs might have an internal power supply which works over that voltage range?

[Martin Brown]

They all do pretty much since LEDs are constant current drive.

As the voltage falls the bulb merely draws more current to maintain constant brightness (which is how it fights with a classical dimmer).

The supply voltage on Saturday was too low for my PC to stay alive so definitely <100v and it made the DECT phone go completely berserk. I measured it at about 90 but it was very much a moving target.

One thing that analogue meters are a lot better at.

[Fredxx]

I did wonder if there were any LED lamps that might be compatible with leading edge dimmers. I couldn't find any.

It seems to me you might have to change its internals to a trailing edge, and only then might you might find compatible lamps.

Or continue with incandescent?

[Theo]

Going halogen would save about a third off the power consumption and should still work with the existing dimmer.

If it's only on for a short period each day, maybe the actual energy consumption is small anyway?

Theo

[Dave Plowman (News]

LEDs need a special type of dimmer. Known (IIRC) as trailing edge. Most older ones won't work with LEDs - even if the LED says dimmable, and not all do.

[Brian]

Certainly the ‘touch’ dimmers I’ve seen have been labelled as not being suitable for LED lambs.

Ordinary dimmers, typically found in wall plate ‘switches’ do seem to work with dimmable LEDs, although trailing edge ones are recommended. The older leading edge ones seem to ‘hum’. Some have a preset to set the min light level. Whether those hum, I’m not sure. I’ve seen claims using leading edge dimmers can shorten the life of LED lambs and/ or cause flickering. While I have LE dimmers and LED lamps, we tend not to use them on dim and haven’t noticed any issues.

As an aside, before I was able to find some suitable LED bulbs for some wall lights we especially like, I bought a stock of bulbs ( golf ball size) which have a quartz bulb inside. That is, a bulb with the golf ball glass. I’ve never used them but, during my research, I found conflicting information re dimming quartz bulbs.

[Brian]

LEDs, dimmable ones, will work with a LE dimmer. You may hear a ‘hum’ at low settings and there are claims it reduces lamp life and/or causes flickering.

We have a couple of double LE dimmers we use with LED lamps, a centre light and wall lights in two different rooms. While we tend not to use the dimmers as dimmers ( just on / off), I’ve tried them as dimmers. I can hear a slight hum on high dim ( low light) but haven’t seen any flickering.

I actually bought ‘LED’ compatible dimmers, when they arrived they clearly stated LED compatible etc, they have a preset to set the low level,….They are leading edge. I didn’t both fitting them.

[Brian Gaff]

Was it a breaker though, or some other fault? I remember quite a while ago a bloke around here described a situation with one of these touch lights with a dimable led where put the bayonet in one way around and it wobbled in brightness all the time, the other way and it worked correctly. My guess is that the psus in leds are pretty cheap and cheerful and so are the mass produced touch dimmers. I got rid of mine as I kept getting tingles off of the body of the lamp. Brian

[Martin Brown]

If you don't dim them then you probably won't ever see a problem. The issue is that the LED unit by default will draw ever more current to try and maintain constant current in the LED until something goes pop.

Very bad for them. The whole idea of quartz halogen bulbs is that the glass envelope gets hot enough to allow the halogen to react with the tungsten that condenses there allowing it to move back to the filament where it is decomposed back into tungsten metal again.

Running them dimmed will slowly coat the envelope in bright tungsten metal and then you won't need to use the dimmer to get lower output.

[Max Demian]

I've heard that was a problem with "dim dipped" headlights on cars, where the headlamp bulbs were connected in series if the side lights were on while the ignition was on. (These were a legal requirement for a few years I believe.)

[zall]

Yep, plug a Philips Hue bluetooth bulb into it instead of the incandescent lamp. Works fine and dimmable.

[zall]

That's not right. A Philips Hue bluetooth bulb will work fine.

Not when it is a smart bulb.

Doesn't happen with a Philips Hue bluetooth bulb.

[Rod Speed]

Or use a Philips Hue bluetooth bulb in it.

[Brian]

Ahh, that makes sense and cuts through the conflicting information I recall. Thank you.

[RJH]

Is it one of those capacitive tap and it dims in stages types? I have one and tried a dimming LED - works fine, but gives off a high piched squeal at all but the brightest setting.

[Martin Brown]

I get the impression you are a shill with shares in Philips.

[zall]

More fool you. I JUST have a number of their products and find that they work very well indeed.

Not cheap but cheaper with the very common discount offers on Amazon and work very well indeed and are very well designed.

Not perfect, no led panels for example.