Been fitting new kitchen .... one of the last job was fitting 3 new
hanging lights. in and working (well sort of)

Wife had bought LED 'filament' decorative bulbs ...... they work fine
on full power or can be dimmed ... but not turned off .....
Dimmer is type you press button it dims to off .... with theses bulbs it
dims to off and then back to low.

First off thought dimmer was faulty - but put in some standard GLS bulbs
and it works fine.

After searching specs it does say non-dimmable (but not in advert or on
packaging)

I'm going to have to find dimmable LED .............. but what makes an
LED bulb dimmable or not ?

How the psu is designed. obviously if the design attempts to keep the light
working no matter how mangled the waveform or how variable the voltage, its
not going to dim very well!
Brian

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"rick" wrote in message
...
Been fitting new kitchen .... one of the last job was fitting 3 new
hanging lights. in and working (well sort of)

Wife had bought LED 'filament' decorative bulbs ...... they work fine on
full power or can be dimmed ... but not turned off .....
Dimmer is type you press button it dims to off .... with theses bulbs it
dims to off and then back to low.

First off thought dimmer was faulty - but put in some standard GLS bulbs
and it works fine.

After searching specs it does say non-dimmable (but not in advert or on
packaging)

I'm going to have to find dimmable LED .............. but what makes an
LED bulb dimmable or not ?

On Sunday, 1 December 2019 19:46:48 UTC, rick wrote:
Been fitting new kitchen .... one of the last job was fitting 3 new
hanging lights. in and working (well sort of)

Wife had bought LED 'filament' decorative bulbs ...... they work fine
on full power or can be dimmed ... but not turned off .....
Dimmer is type you press button it dims to off .... with theses bulbs it
dims to off and then back to low.

First off thought dimmer was faulty - but put in some standard GLS bulbs
and it works fine.

After searching specs it does say non-dimmable (but not in advert or on
packaging)

I'm going to have to find dimmable LED .............. but what makes an
LED bulb dimmable or not ?

I don't think it's down to makes. A company eithe rmakes dimmable or non-dimmable they can make both, dimmable are usually more expensive.

On 01/12/2019 19:46, rick wrote:
Been fitting new kitchen .... one of the last job was fitting 3 new
hanging lights. in and working (well sort of)

Wife had bought LED 'filament' decorative bulbsÂ* ...... they work fine
on full power or can be dimmed ... but not turned off .....
Dimmer is type you press button it dims to off .... with theses bulbs it
dims to off and then back to low.

First off thought dimmer was faulty - but put in some standard GLS bulbs
and it works fine.

After searching specs it does say non-dimmable (but not in advert or on
packaging)

I'm going to have to find dimmable LED .............. but what makes an
LED bulb dimmable or not ?

If you put one tungsten bulb in it usually lets the LEDs dim properly.

Bill

On Sun, 01 Dec 2019 19:46:43 +0000, rick wrote:

Been fitting new kitchen .... one of the last job was fitting 3 new
hanging lights. in and working (well sort of)

Wife had bought LED 'filament' decorative bulbs ...... they work fine
on full power or can be dimmed ... but not turned off .....
Dimmer is type you press button it dims to off .... with theses bulbs it
dims to off and then back to low.

First off thought dimmer was faulty - but put in some standard GLS bulbs
and it works fine.

After searching specs it does say non-dimmable (but not in advert or on
packaging)

I'm going to have to find dimmable LED .............. but what makes an
LED bulb dimmable or not ?

I find the dimmables do not start from zero luminance but some way up.

On Tuesday, 3 December 2019 11:31:22 UTC, Bill Wright wrote:
On 01/12/2019 19:46, rick wrote:
Been fitting new kitchen .... one of the last job was fitting 3 new
hanging lights. in and working (well sort of)

Wife had bought LED 'filament' decorative bulbsÂ* ...... they work fine
on full power or can be dimmed ... but not turned off .....
Dimmer is type you press button it dims to off .... with theses bulbs it
dims to off and then back to low.

First off thought dimmer was faulty - but put in some standard GLS bulbs
and it works fine.

After searching specs it does say non-dimmable (but not in advert or on
packaging)

I'm going to have to find dimmable LED .............. but what makes an
LED bulb dimmable or not ?

If you put one tungsten bulb in it usually lets the LEDs dim properly.

Bill

That's because most dimmers have a minium wattage rating that they can dim to, or words to that effect, I think mine was advertised as 5watts.
if you go below that then the dimmer just switches itself to off.

In article ,
pinnerite wrote:
On Sun, 01 Dec 2019 19:46:43 +0000, rick wrote:

Been fitting new kitchen .... one of the last job was fitting 3 new
hanging lights. in and working (well sort of)

Wife had bought LED 'filament' decorative bulbs ...... they work fine
on full power or can be dimmed ... but not turned off .....
Dimmer is type you press button it dims to off .... with theses bulbs it
dims to off and then back to low.

First off thought dimmer was faulty - but put in some standard GLS bulbs
and it works fine.

After searching specs it does say non-dimmable (but not in advert or on
packaging)

I'm going to have to find dimmable LED .............. but what makes an
LED bulb dimmable or not ?

I find the dimmables do not start from zero luminance but some way up.

Even where you alter a plain LED via the amount of current passing through
it, can be difficult to get a smooth increase from zero. But easier to
reduce to zero smoothly. I'd guess they need some sort of start up kick.

--
*What hair colour do they put on the driver's license of a bald man? *

Dave Plowman London SW
To e-mail, change noise into sound.

On 04/12/2019 14:30, Dave Plowman (News) wrote:
In article ,
pinnerite wrote:
On Sun, 01 Dec 2019 19:46:43 +0000, rick wrote:

Been fitting new kitchen .... one of the last job was fitting 3 new
hanging lights. in and working (well sort of)

Wife had bought LED 'filament' decorative bulbs ...... they work fine
on full power or can be dimmed ... but not turned off .....
Dimmer is type you press button it dims to off .... with theses bulbs it
dims to off and then back to low.

First off thought dimmer was faulty - but put in some standard GLS bulbs
and it works fine.

After searching specs it does say non-dimmable (but not in advert or on
packaging)

I'm going to have to find dimmable LED .............. but what makes an
LED bulb dimmable or not ?

I find the dimmables do not start from zero luminance but some way up.

Dimmable requires that the LED constant current supply accepts the
waveform that the dimmer feeds it without fighting against it. Worst
case as you try to dim the LED unit it draws ever more current from a
smaller and smaller part of the mains cycle until something goes pop!

Even where you alter a plain LED via the amount of current passing through
it, can be difficult to get a smooth increase from zero. But easier to
reduce to zero smoothly. I'd guess they need some sort of start up kick.

Bare high brightness 5mm LEDs are pretty linear with current drive from
about 5uA (and upwards to 20mA) these days. You need dark adaption to
see them at such very low drive currents but they are still lit.

Power white LEDs are a little less linear due to thicker phosphor layer.
Bridging the switch of a simple LED torch with 1M makes it findable in
the pitch dark without appreciably altering the battery life.

--
Regards,
Martin Brown

On Wednesday, 4 December 2019 14:39:46 UTC, Dave Plowman (News) wrote:
In article ,
pinnerite wrote:
On Sun, 01 Dec 2019 19:46:43 +0000, rick wrote:

Been fitting new kitchen .... one of the last job was fitting 3 new
hanging lights. in and working (well sort of)

Wife had bought LED 'filament' decorative bulbs ...... they work fine
on full power or can be dimmed ... but not turned off .....
Dimmer is type you press button it dims to off .... with theses bulbs it
dims to off and then back to low.

First off thought dimmer was faulty - but put in some standard GLS bulbs
and it works fine.

After searching specs it does say non-dimmable (but not in advert or on
packaging)

I'm going to have to find dimmable LED .............. but what makes an
LED bulb dimmable or not ?

I find the dimmables do not start from zero luminance but some way up.

Even where you alter a plain LED via the amount of current passing through
it, can be difficult to get a smooth increase from zero. But easier to
reduce to zero smoothly. I'd guess they need some sort of start up kick.

Well they are called diodes and that means getting above the threshold which is noramlly 0.6V to 0.7V for a silicon and 0.3V for gernamium but as yuo had things so you get colour I guess that changes things.

if you take a basic LED they typically don't start conducting below 1V

And it;s easy if yuo start from the LED being ON and then slowlty turn it off as you'll still get a bit of persistance of vision from the eyes, which will mask the delay in turning an LED from OFF to 1V to it's conducting voltage.