The Lemon Fool

XFool wrote:Why is everything getting more and more complicated?

You mean complications such as dimmers?

V8

Next question (wrong thread?):

Exactly why do leading edge dimmers not work with dimmable LED lights and exactly why do trailing edge dimmers work with dimmable LEDs (assuming they do). For that matter, what is the difference between dimmable and non dimmable LEDs (apart from the obvious...). Something to do with their built in power supply, presumably?

Anyone know the answers, please?

XFool wrote:Next question (wrong thread?):

Exactly why do leading edge dimmers not work with dimmable LED lights and exactly why do trailing edge dimmers work with dimmable LEDs (assuming they do). For that matter, what is the difference between dimmable and non dimmable LEDs (apart from the obvious...). Something to do with their built in power supply, presumably?

Anyone know the answers, please?

I don't know what your base level understanding is electronics/electric stuff
- but start with this for a review of the dimming differences https://www.lamps-on-line.com/leading-trailing-edge-led-dimmers

The LEDs themselves are effectively working at DC and your two ways of controlling the amount of light emitted are by changing the current through it or by strobing it super quick
- how you get there from the AC supply is where the power gubbins of the LED does it's magic

...but anyway if you look at the difference in the output of the trailing edge vs the leading edge from the link I gave, you'll see that the abrupt change in voltage is at the end rather than start.
If that abrupt change (or edge) is at the start you get a hard inrush of current every cycle, this gives you buzzing and makes the thing altogether more twitchy and harder to control
- the alternative with that edge at the end gives a soft rise every cycle that is nicer (less stressing) on low voltage electronic equipment downstream to deal with.... but you can't just implement it with a cheap triac

Dod101 wrote:Why are you keeping old tungsten filament bulbs? Hideously expensive compared to the equivalent LED ones. Admittedly LED are fairly expensive to buy in the first place but it is a one off cost and the electricity saving is huge.

Dod

Not in my hovel it isn't!

I find one or another of my LED lamps packs up about once every couple of months and its only a tiny cottage.

As mentioned upthread there are so many combinations now of power, socket type, socket size and bulb shape that I have a dedicated shelf full of spare LED bulbs in the pantry; just as many as I ever had when we used incandescent.

Pantry! Next you'll be needing to light the larder!

Mike4 wrote:

Dod101 wrote:Why are you keeping old tungsten filament bulbs? Hideously expensive compared to the equivalent LED ones. Admittedly LED are fairly expensive to buy in the first place but it is a one off cost and the electricity saving is huge.

Dod

Not in my hovel it isn't!

I find one or another of my LED lamps packs up about once every couple of months and its only a tiny cottage.

As mentioned upthread there are so many combinations now of power, socket type, socket size and bulb shape that I have a dedicated shelf full of spare LED bulbs in the pantry; just as many as I ever had when we used incandescent.

I would suggest that there is something wrong with your electricity supply. I have had LED bulbs in my kitchen, bathrooms, and reading lamps in my living room for about five years and I can only think of one that has blown in that time. The savings in electricity are dramatic.

Dod

PS Or your LED supplier. Plenty cheapie ones around.

D

Poundland is my go to. I have GU10 spots in the kitchen and E14 and E27 screw ins everywhere else. The bulbs are cheap as chips, have warm white and daylight white options and after years of experience I haven't had any issue with premature failure.

I've no idea if they're dimmable because I removed my dimmer switches ages ago in favour of separate light fittings for mood lighting.

Dicky99 wrote:
I've no idea if they're dimmable because I removed my dimmer switches ages ago in favour of separate light fittings for mood lighting.

"mood lighting"

Is that Southern for "lamp"?

Mike4 wrote:I find one or another of my LED lamps packs up about once every couple of months and its only a tiny cottage.

That does seem odd. We have had LED lights throughout the house for longer than I care to remember. Wall lights, ceiling lights, fluorescent striplight replacements, you name it.
Never had a single failure.

bh

Dod101 wrote:

Mike4 wrote:
Not in my hovel it isn't!

I find one or another of my LED lamps packs up about once every couple of months and its only a tiny cottage.

As mentioned upthread there are so many combinations now of power, socket type, socket size and bulb shape that I have a dedicated shelf full of spare LED bulbs in the pantry; just as many as I ever had when we used incandescent.

I would suggest that there is something wrong with your electricity supply. I have had LED bulbs in my kitchen, bathrooms, and reading lamps in my living room for about five years and I can only think of one that has blown in that time. The savings in electricity are dramatic.

Dod

PS Or your LED supplier. Plenty cheapie ones around.

D

It might be worth getting the supply checked...(or any big inductive loads on it!) if LEDs are blowing regularly (over/under voltage, surges) it could be prematurely aging other more expensive gear

That said if they're sitting wonky in bayonet fittings I'd start there!

While the LED itself doesn't produce much heat the power conversion gubbins might, especially if the input supply isn't where it was expecting it to be

I haven't needed to buy any LEDs since moving to the new place in July 2015 when I swapped all the existing stock. We still have some tungsten, and halogens in a cupboard somewhere if anyone wants them. I remember at the time LEDhut was getting high praise for quality and guarantee so I used them. I needed about 20 lamps for the whole property, we have a 2 bed flat. A chum moved at the same time to a larger property he had 20 lamps in his kitchen alone.

When we moved in here I replaced all the downlighters with LED.

It was a faff getting the right sizes, modifying the holes, and there is always the worry of one failing an not being able to get a match.

Consequently we bought a spare of each type, thus guranteeing either no failures whatsoever whilst we live here, or 2 at once.

Paul

kempiejon wrote:I remember at the time LEDhut was getting high praise for quality and guarantee so I used them. I needed about 20 lamps for the whole property, we have a 2 bed flat. A chum moved at the same time to a larger property he had 20 lamps in his kitchen alone.

91 bulbs at Bungee Towers, although 18 of those are in candelabra lamps that don't get switched on much, so they're non-LED and we don't mind if they radiate a bit of heat. Seven LEDs in outside lamps, and they usually last 5 to 8 years despite the weather battering at them. Yes, and 20 in the kitchen, including downlighters.

Agree that there's something amiss if LEDs keep on popping, though. It might just be a dicky deep-rural supply, of course. (Mike4, ISTR you saying that you get a lot of power cuts, and that you have an overhead power supply line to your house?)

In my last village house, the local farmer used heavy-duty equipment that made the lights flicker. Then one day, there was a loud bang and my printer and computer both went up in smoke. (Literally. There were flames coming from the printer!)

Power company came in and said this was due to power surges, which were pretty normal when things like grain driers were in use. He'd also seen up to 500 volts coming through urban circuits - only momentarily, of course, and usually caused by high-drain stuff like fairground equipment. Either way, I was able to claim for the techno damage, so honour was satisfied. Oh,and I use a UPS for the computers nowadays. Can't be too careful.

BJ

bungeejumper wrote:Agree that there's something amiss if LEDs keep on popping, though. It might just be a dicky deep-rural supply, of course. (Mike4, ISTR you saying that you get a lot of power cuts, and that you have an overhead power supply line to your house?)

In my last village house, the local farmer used heavy-duty equipment that made the lights flicker. Then one day, there was a loud bang and my printer and computer both went up in smoke. (Literally. There were flames coming from the printer!)

Power company came in and said this was due to power surges, which were pretty normal when things like grain driers were in use. He'd also seen up to 500 volts coming through urban circuits - only momentarily, of course, and usually caused by high-drain stuff like fairground equipment. Either way, I was able to claim for the techno damage, so honour was satisfied. Oh,and I use a UPS for the computers nowadays. Can't be too careful.

BJ

Possibly this is it. Yes the posh end of the village is little thin overhead lines for about five miles as far as I can tell, and I get a power cut of five or ten hours every two or three weeks when the lines presumably get damaged. I've long ago given up re-setting my electric radio alarm clock for example.

Its not a big deal and I have bigger fish to fry than to quibble with the leccy company about it. One bulb failure out of 25 (just counted them!) every two or three months just isn't that big a deal, but I had to challenge the assertion upthread that they last for ever!

DrFfybes wrote:
Consequently we bought a spare of each type, thus guranteeing either no failures whatsoever whilst we live here, or 2 at once.

Paul

The Gods were happy with your choices
- much safer than saying stuff like "I never get punctures"

Mike4 wrote:

Dod101 wrote:Why are you keeping old tungsten filament bulbs? Hideously expensive compared to the equivalent LED ones. Admittedly LED are fairly expensive to buy in the first place but it is a one off cost and the electricity saving is huge.

Dod

Not in my hovel it isn't!

I find one or another of my LED lamps packs up about once every couple of months and its only a tiny cottage.

Not in ours either though so far the costly failures have mostly been confined to the Status make of 100W ‘equivalents’ of the filament variety. We’ve had 4 or 5 failures of these (plus 2 or 3 Ikea 40W equivalent miniatures) in the last year. The failures have involved 1 or 2 of the filament strands failing followed by the lamp flashing periodically (possibly due to the power supply not coping well with the change of load).

I guess that the cost of failed LEDs has easily outstripped the total cost of failed incandescents since we’ve lived here but I’m too lazy to estimate whether the running costs have compensated.

Well, I had a very old 1980s inline Habitat dimmer hanging around. So I tried that in place of the lamp's inline dimmer, with the lamp and new LED bulb. It worked better! Though it is less sophisticated than the original, with no state memory from switch off to switch on like the original. It is based on the Siemens S576 dimmer chip:

https://bestengineeringprojects.com/touch-dimmer-circuit/

The Habitat model has an inductor on board, unlike in the circuit shown above. Possibly like in this circuit with the Siemens S566B chip:

https://www.eeweb.com/siemens-s566b-electronic-touch-dimmer/

"But once a new short touch is provided, the lamp will turn ON with the last saved level of intensity. From the level that has been stored, the control of intensity will start at this level."

So that chip does have a memory like the lamp's original dimmer. Thinks: I wonder if an S566 is a drop in replacement for an S576?

What does the original light dimmer use?: Two chips. Seemingly a 555 (a timer) and a 12C508A which is... an 8-Pin, 8-Bit CMOS Microcontroller!

Bit of an overkill? Surely a Siemens S566 would do the same job?

I notice the board for the original dimmer has two signal inputs: marked PS, the one in use and P which is unused
I was wondering if the other input could be for trailing edge use (wishing!) It lacks two onboard series capacitor(?) links that the other one has, plus there is a missing wire link on the board directing it to other parts of the cct than the PS input. There are also two unused selection headers on the board, marked A and B. Don't suppose I can find any data on it, the manufacturer on the housing is Relco model RT78SCG.

Definitely not for LEDs then: https://elektrogros.ch/en/schnurdimmer-rt78scg-n-sensor-230v-40-300w-schwarz

And there's the lamp, too. Even a small child can use it...

servodude wrote:I don't know what your base level understanding is electronics/electric stuff
- but start with this for a review of the dimming differences https://www.lamps-on-line.com/leading-trailing-edge-led-dimmers

The LEDs themselves are effectively working at DC and your two ways of controlling the amount of light emitted are by changing the current through it or by strobing it super quick
- how you get there from the AC supply is where the power gubbins of the LED does it's magic

...but anyway if you look at the difference in the output of the trailing edge vs the leading edge from the link I gave, you'll see that the abrupt change in voltage is at the end rather than start.
If that abrupt change (or edge) is at the start you get a hard inrush of current every cycle, this gives you buzzing and makes the thing altogether more twitchy and harder to control
- the alternative with that edge at the end gives a soft rise every cycle that is nicer (less stressing) on low voltage electronic equipment downstream to deal with.... but you can't just implement it with a cheap triac

Thanks for the information, servodude.

XFool wrote:

servodude wrote:I don't know what your base level understanding is electronics/electric stuff
- but start with this for a review of the dimming differences https://www.lamps-on-line.com/leading-trailing-edge-led-dimmers

The LEDs themselves are effectively working at DC and your two ways of controlling the amount of light emitted are by changing the current through it or by strobing it super quick
- how you get there from the AC supply is where the power gubbins of the LED does it's magic

...but anyway if you look at the difference in the output of the trailing edge vs the leading edge from the link I gave, you'll see that the abrupt change in voltage is at the end rather than start.
If that abrupt change (or edge) is at the start you get a hard inrush of current every cycle, this gives you buzzing and makes the thing altogether more twitchy and harder to control
- the alternative with that edge at the end gives a soft rise every cycle that is nicer (less stressing) on low voltage electronic equipment downstream to deal with.... but you can't just implement it with a cheap triac

Thanks for the information, servodude.

It's not the whole story but it probably covers the big difference between the two schemes
It's one of those cases where an "X" (in this case "dimmer") isn't really as clear cut and "obviously a thing" as it might seem, unless you spend your life in that domain ( not sure if that's a good or bad thing though )

Call me paranoid if you like, but it appears to me that nearly all the messages on this thread have been posted after dark, when presumably, people writing those messages are burning the midnight LED.