Will never understand them.

Have a 9 gang Crabtree grid panel. Originally fitted with Home Automation
dimmers, in the 70s.

Many years ago, I got offered a carton of Dimmalite push button dimmers to
fit the old Crabtree grid - after it had been changed. At a silly price.
Before the days of CFLs and LEDs. They are rated at 400w resistive or 250w
inductive. I like the action and looks. Touch the single button for on.
And again for off. Hold it down and the level changes - a double press the
other way.

Replaced all in the 9 gang panel with them, but of course kept the old
Home Automation.

When dimmable LEDs arrived, did try one with this dimmer. Didn't work.

So basically left this room with tungsten.

With the increase in leccy prices decided to change the most used to LED.
And intended fitting V-Pro dimmers to the Crabtree grid mountings - not an
easy job. But out of curiosity tried one of the new LED golfball SBC in
the table lamp on its own dimmer. And was surprised to find they dim just
fine. As did a couple of GU10 lighting the inside of a (not used)
fireplace.

So wondering if the LED design had changed? The original LED I tried did
dim just fine with a LED dimmer. Not a minimum load thing either, as the
golf balls are only 4 watt. And worked with just one.

--
*If a pig loses its voice, is it disgruntled? *

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

On 20/11/2022 15:27, Dave Plowman (News) wrote:
<snip>
>
> So wondering if the LED design had changed? The original LED I tried did
> dim just fine with a LED dimmer. Not a minimum load thing either, as the
> golf balls are only 4 watt. And worked with just one.
>

I can provide another example in support of a "suck it and see"
approach. The hike in prices led me to try some cheap Chinese LED R7s
replacements advertised as dimmable in a pair of 1990s uplighters 'er
indoors refuses to give up. To my surprise they dim happily with the
equally ancient in-line slide dimmers. Buzzing not audible on even the
lowest setting unless you stand right next to them.

--
Robin
reply-to address is (intended to be) valid

On 20/11/2022 15:27, Dave Plowman (News) wrote:
> Will never understand them.
>
> Have a 9 gang Crabtree grid panel. Originally fitted with Home Automation
> dimmers, in the 70s.
>
> Many years ago, I got offered a carton of Dimmalite push button dimmers to
> fit the old Crabtree grid - after it had been changed. At a silly price.
> Before the days of CFLs and LEDs. They are rated at 400w resistive or 250w
> inductive. I like the action and looks. Touch the single button for on.
> And again for off. Hold it down and the level changes - a double press the
> other way.
>
> Replaced all in the 9 gang panel with them, but of course kept the old
> Home Automation.
>
> When dimmable LEDs arrived, did try one with this dimmer. Didn't work.
>
> So basically left this room with tungsten.
>
> With the increase in leccy prices decided to change the most used to LED.
> And intended fitting V-Pro dimmers to the Crabtree grid mountings - not an
> easy job. But out of curiosity tried one of the new LED golfball SBC in
> the table lamp on its own dimmer. And was surprised to find they dim just
> fine. As did a couple of GU10 lighting the inside of a (not used)
> fireplace.
>
> So wondering if the LED design had changed? The original LED I tried did
> dim just fine with a LED dimmer. Not a minimum load thing either, as the
> golf balls are only 4 watt. And worked with just one.

There are leading and trailing edge dimmers. An old one designed for
used with filament lamps will be leading edge, whether they work with
dimmable LED lamps designed for leading edge you will have to check.

Not all dimmable LED lamps are the same, and some will work with one
type of dimmer, but not the other.

This article goes over the salient points:
https://greenlighting.co.uk/leading-trailing-edge-dimmers-explained/

I suspect the unknown minimum load requirement may be a show-stopper.
Incandescent lamps are inherently non-linear and also when run at low
levels had a lower resistance and therefore a higher current than you
might expect at low light levels.

On 11/20/2022 10:27 AM, Dave Plowman (News) wrote:
> Will never understand them.
>
> Have a 9 gang Crabtree grid panel. Originally fitted with Home Automation
> dimmers, in the 70s.
>
> Many years ago, I got offered a carton of Dimmalite push button dimmers to
> fit the old Crabtree grid - after it had been changed. At a silly price.
> Before the days of CFLs and LEDs. They are rated at 400w resistive or 250w
> inductive. I like the action and looks. Touch the single button for on.
> And again for off. Hold it down and the level changes - a double press the
> other way.
>
> Replaced all in the 9 gang panel with them, but of course kept the old
> Home Automation.
>
> When dimmable LEDs arrived, did try one with this dimmer. Didn't work.
>
> So basically left this room with tungsten.
>
> With the increase in leccy prices decided to change the most used to LED.
> And intended fitting V-Pro dimmers to the Crabtree grid mountings - not an
> easy job. But out of curiosity tried one of the new LED golfball SBC in
> the table lamp on its own dimmer. And was surprised to find they dim just
> fine. As did a couple of GU10 lighting the inside of a (not used)
> fireplace.
>
> So wondering if the LED design had changed? The original LED I tried did
> dim just fine with a LED dimmer. Not a minimum load thing either, as the
> golf balls are only 4 watt. And worked with just one.
>

Here is a bulb that works with both leading and trailing.

https://www.cromptonlamps.com/Catalogue/LED/Thermal-Plastic/GLS/100W-Equivalent/LED-GLS-Thermal-Plastic-Dimmable-14W-2700K-ES-E27-11908

And if the silicon exists (the IC inside listening for
both edges), then other brands should be able to advertise
the same feature.

*******

They have different loading rules here, for leading versus trailing
dimmers. The power rating of the dimmer, is affected by the load type
(incandescent or LED). Even an incandescent has an inrush behavior,
but it's only 2x the current when the bulb is cold.

https://greenlighting.co.uk/leading-trailing-edge-dimmers-explained/

Paul

It has to be the way the power supply in the led lamp is made. Normally
dimming them seems to be done in two ways. pulse width modulation, and
voltage. LEDs are after all DC devices. That leaves a lot of ways to drive
them!

Brian

--

--:
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
briang1@blueyonder.co.uk
Blind user, so no pictures please
Note this Signature is meaningless.!
"Dave Plowman (News)" <dave@davenoise.co.uk> wrote in message
news:5a4a5d5285dave@davenoise.co.uk...
> Will never understand them.
>
> Have a 9 gang Crabtree grid panel. Originally fitted with Home Automation
> dimmers, in the 70s.
>
> Many years ago, I got offered a carton of Dimmalite push button dimmers to
> fit the old Crabtree grid - after it had been changed. At a silly price.
> Before the days of CFLs and LEDs. They are rated at 400w resistive or 250w
> inductive. I like the action and looks. Touch the single button for on.
> And again for off. Hold it down and the level changes - a double press the
> other way.
>
> Replaced all in the 9 gang panel with them, but of course kept the old
> Home Automation.
>
> When dimmable LEDs arrived, did try one with this dimmer. Didn't work.
>
> So basically left this room with tungsten.
>
> With the increase in leccy prices decided to change the most used to LED.
> And intended fitting V-Pro dimmers to the Crabtree grid mountings - not an
> easy job. But out of curiosity tried one of the new LED golfball SBC in
> the table lamp on its own dimmer. And was surprised to find they dim just
> fine. As did a couple of GU10 lighting the inside of a (not used)
> fireplace.
>
> So wondering if the LED design had changed? The original LED I tried did
> dim just fine with a LED dimmer. Not a minimum load thing either, as the
> golf balls are only 4 watt. And worked with just one.
>
> --
> *If a pig loses its voice, is it disgruntled? *
>
> Dave Plowman dave@davenoise.co.uk London SW
> To e-mail, change noise into sound.