TOT: LED light bulbs

[Woody]

Can anyone give me a <definitive> answer to this one please?

One can easily buy 'dimmable' LED bulbs, but there are many bulbs that
are stated to be non-dimmable.

Would I be right in assuming:-

1 So-called dimmable bulbs are designed to work with ordinary
incandescent (i.e. leading egde) dimmers?

2 Any LED bulb can be safely dimmed with a trailing edge dimmer whether
specified as being suitable for dimming or not?

All of our LED bulbs were purchased as dimmable, but I found out that
Screwfix do trailing edge dimmers only a little more expensive than a
standard dimmer so I fitted those and have had no trouble at all.

Thoughts of the group would be much appreciated.

[John Williamson]

On 09/11/2022 17:36, Woody wrote:

> 2 Any LED bulb can be safely dimmed with a trailing edge dimmer whether
> specified as being suitable for dimming or not?
>

Non dimmable LEDs are designed to give a constant light output over a
wide range of input voltages, so as you dim them, they stay bright until
you drop the voltage too low, when they tend to cut off.


--
Tciao for Now!

John.

[Andy Burns]

Woody wrote:

> Would I be right in assuming:-
>
> 1 So-called dimmable bulbs are designed to work with ordinary incandescent (i.e.
> leading egde) dimmers?

not necessarily, some LED lamps require trailing edge dimmers

> 2 Any LED bulb can be safely dimmed with a trailing edge dimmer whether
> specified as being suitable for dimming or not?

Don't think so, they might just have a capacitive dropper and be flickery.

> All of our LED bulbs were purchased as dimmable, but I found out that Screwfix
> do trailing edge dimmers only a little more expensive than a standard dimmer so
> I fitted those and have had no trouble at all.

I like the varilight v-pro dimmers, they are "programmable" to work with any
type of lighting.

[Brian Gaff]

That is right, to a degree. They contain a switch mode psu, similar to the
sort you get in those plug inusb power supplies. However though they are
quite efficient they are dissipating more power on the higher voltages, but
not as much as, say, an older type voltage regulator does.
I don't use lights much these days, but I have had friends complaiing at
this sort of thing.
Brian

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[Andy Burns]

Brian Gaff wrote:

> That is right, to a degree. They contain a switch mode psu

The cheaper, nastier LEDs don't.

[MB]

Reminds of a call on Jeremy Vine's programme a few days ago.

Someone was talking about the high cost of electricity and said they
were being very careful with their heating.

But they also said they were leaving all their lights off! Shows how
many have no appreciation of the cost difference between running a LED
light taking only a few watts and electric heating.

[Max Demian]

On 10/11/2022 10:19, Brian Gaff wrote:

> That is right, to a degree. They contain a switch mode psu, similar to the
> sort you get in those plug inusb power supplies. However though they are
> quite efficient they are dissipating more power on the higher voltages, but
> not as much as, say, an older type voltage regulator does.
> I don't use lights much these days, but I have had friends complaiing at
> this sort of thing.

I would have thought that the problem results from interference between
the dimmer circuit and the LED's PSU in some way.

--
Max Demian

[Max Demian]

On 09/11/2022 17:36, Woody wrote:

One day all lighting circuits will be low voltage DC. Then we can use
PWM dimmers and there won't be any problems. And with RGB LEDs we can
change the hue at will. And no-one will get a shock when they touch the
cables.

(Just for fun a few years ago I made a PWM dimmer based on circuits
found on the Internet that drives a 12V LED strip.)

--
Max Demian

[Roderick Stewart]

On Thu, 10 Nov 2022 11:38:34 +0000, Max Demian
<max_d...@bigfoot.com> wrote:

>One day all lighting circuits will be low voltage DC. Then we can use
>PWM dimmers and there won't be any problems. And with RGB LEDs we can
>change the hue at will. And no-one will get a shock when they touch the
>cables

One day maybe, but which year?

Rod.

[John Williamson]

If you have grid power available, it's not worth the bother of
installing a low voltage supply circuit to do it, while for off grid
uses, it happened a while ago. I live on a boat, and all my 12 volt
lights got replaced by LED equivalents about five years ago.

[steve1...@outlook.com]

My wife bought a new bulb yesterday. It's LED and works on our UK 240
volt mains supply. All the pessary electronics are built in to the
bulb holder. No separate parts are needed.

Steve

[steve1...@outlook.com]

Of course that should be necessary.

Steve

[John Williamson]

On 11/11/2022 10:55, steve1...@outlook.com wrote:
> On Fri, 11 Nov 2022 10:16:56 +0000, John Williamson

> My wife bought a new bulb yesterday. It's LED and works on our UK 240
> volt mains supply. All the pessary electronics are built in to the
> bulb holder. No separate parts are needed.
>
>

The problem with the cheaper types of those is that they emit a lot of
RFI, which can wipe out weak AM signals on all the common wavebands.

I use 240 volt LED worklights, but I don't listen on AM and as I live in
a steel box anyway, the RFI doesn't affect the neighbours.

[Roderick Stewart]

Every light in my house is LED and they don't interfere with anything.

LEDs are practically standard now, and they consume about a tenth of
the power of incandescent bulbs, so why would anyone want to buy
anything else even if they could? Radio is FM in the car or internet
at home, some people listen to DAB, and youngsters listen to stuff on
their phones, but it's been many years since I heard anyone listen to
anything on AM radio. I'm not even sure if you can still buy one.

Rod.

[NY]

"John Williamson" <johnwil...@btinternet.com> wrote in message

news:jt6p6o...@mid.individual.net...

I spent ages trying to track down why recordings from the PSB1 Freeview
multiplex got a lot of interference every evening. It took me an
embarrassingly long time to relate it to times when the lights were turned
on. I gradually narrowed it down to one bulb of several GU10 LED bulbs in my
study which is directly below the TV aerial. When that bulb was turned on,
PSB1 showed a very poor SNR (as seen by a DVB-USB tuner connected to the
Raspberry Pi that I use for recording TV). All other multiplexes had no
effect.

I replaced that GU10 bulb with one of a different make, and moved the
offending GU10 bulb to another part of the house, much further from the TV
aerial, and the problem went away.

[steve1...@outlook.com]

On Fri, 11 Nov 2022 11:15:35 +0000, John Williamson
<johnwil...@btinternet.com> wrote:

>The problem with the cheaper types of those is that they emit a lot of
>RFI, which can wipe out weak AM signals on all the common wavebands.
>

I don't know what it cost. It was a replacement for the last filament
light in our house.

>I use 240 volt LED worklights, but I don't listen on AM and as I live in
>a steel box anyway, the RFI doesn't affect the neighbours.

I have not listened to AM radio stations for decades. I don't know
about my neighbours.

Steve

[John Williamson]

On 11/11/2022 12:15, Roderick Stewart wrote:

> Every light in my house is LED and they don't interfere with anything.
>

Some do, some don't. It depends on the circuitry inside, some is
designed to be low RFI.

> LEDs are practically standard now, and they consume about a tenth of
> the power of incandescent bulbs, so why would anyone want to buy
> anything else even if they could? Radio is FM in the car or internet
> at home, some people listen to DAB, and youngsters listen to stuff on
> their phones, but it's been many years since I heard anyone listen to
> anything on AM radio. I'm not even sure if you can still buy one.
>

I saw a cheap (About a tenner) radio with Medium wave, nine short wave
bands and FM for sale in a shop recently, and medium wave, long wave and
many short wave bands are all still alive and kicking.

Just because your experience is that those whose interests are purely
for popular broadcast news and other programmes don't suffer from
interference on FM and digital doesn't mean that radio amateurs and
those wanting to hear a different version of the news aren't annoyed by
the RFI from cheap LEDs.

I often speak to a guy on line who is a short wave listener, and he has
really bad problems with neighbours' LED lighting blotting out the
weaker stations.

[Liz Tuddenham]

John Williamson <johnwil...@btinternet.com> wrote:

[...]

> I often speak to a guy on line who is a short wave listener, and he has
> really bad problems with neighbours' LED lighting blotting out the
> weaker stations.

I have quite a large long-wire aerial in a good location with a screened
downlead, but found reception on short wave was getting progressively
worse. A friend suggested I should pay more attention to the earth, so
I hammered some stakes into the ground underneath the window of the
bedroom where the receiver was. They were spaced across the front of
the house a few feet apart, wired together with hefty wire which was
soldered on by means of a blowlamp.

Joining this earth to the chassis of the receiver helped enormously but
the real improvement came when I interpersed a proper filter in the
mains lead. Not one of the cheapo socket-strip types, but a home-made
job with bifilar chokes and decent capacitors.

I haven't found a way of getting rid of the deliberately-transmitted
spread-spectrum digital hash that is now an almost continuous foreground
across many of the bands.


--
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

[Scott]

A friend of mine believes it is better to use a battery powered radio
(with Duracell batteries) to reduce use of mains electricity.

[John Williamson]

That doesn't even make sense if they are rechargeable.

[Roderick Stewart]

It doesn't makes sense if they're disposable batteries either because
it takes energy to manufacture them.

There definitely seems to be a widespread belief that NIMBY energy is
equivalent to magic. Out of sight, out of mind.

Rod.

[John Williamson]

On 14/11/2022 12:04, Roderick Stewart wrote:
> On Mon, 14 Nov 2022 11:00:48 +0000, John Williamson
> <johnwil...@btinternet.com> wrote:
>
>> On 14/11/2022 10:12, Scott wrote:

>>> A friend of mine believes it is better to use a battery powered radio
>>> (with Duracell batteries) to reduce use of mains electricity.
>>>
>> That doesn't even make sense if they are rechargeable.
>
> It doesn't makes sense if they're disposable batteries either because
> it takes energy to manufacture them.
>

They are by far the most carbon intensive and polluting way to power
stuff, even if they get recycled.

> There definitely seems to be a widespread belief that NIMBY energy is
> equivalent to magic. Out of sight, out of mind.
>

Many even ignore the embedded CO2 and other pollution in Wind turbines
and the solar panels on their roofs.

[MB]

On 14/11/2022 12:19, John Williamson wrote:
> Many even ignore the embedded CO2 and other pollution in Wind turbines
> and the solar panels on their roofs.

And if you live in a rural area, you will see the number of roads built
to get the things up to the sites (often in what were beautiful areas).

And of course they leave a big lump of the concrete in the ground which
is unlikely to be ever removed.

[Scott]

The argument was on cost rather than environmental grounds. Running a
radio on the mains pushes up the electricity bill :-)

On your second point, obviously you need to make sure batteries are
made in China so that any emissions are part of China's statistics not
ours.

[John Williamson]

On 14/11/2022 13:02, Scott wrote:
> On Mon, 14 Nov 2022 12:04:29 +0000, Roderick Stewart
> <rj...@escapetime.myzen.co.uk> wrote:
>> There definitely seems to be a widespread belief that NIMBY energy is
>> equivalent to magic. Out of sight, out of mind.
>>
> The argument was on cost rather than environmental grounds. Running a
> radio on the mains pushes up the electricity bill :-)
>

Even at the current rip off rates, a pound's worth of battery holds much
less than a penny's worth of grid power. (Using high power AA cells, you
get about 3 watt hours per cell.)

[Scott]

This is of course the argument that I was advancing during the debate
:-)