The dimming profile > behavior on a dimmer

... and a measure of this.

The dimming profile describes how the light source behaves when dimming.

In other words:

What is the brightness of the illuminant related to the dimmer position?


The new index DPA in percent expresses the Dimming Profile Abberation in comparison to the incandescent light bulb.


At the bottom of this page, there is a list of illuminants tested for dimmability.

Basic knowledge:

By dimming (classical leading edge or recent trailing edge), only a part of the sinusoidal mains voltage is supplied to the illuminant. In this case, each half-wave is connected to the illuminant at a particular point in time (leading edge) or truncated at a certain point in time (trailing edge).


In order to avoid large current pulses, the resulting greater load and premature aging of the illuminant with inductive loads (e.g. transformer) a leading edge dimming should be favoured. For dimming capacitive loads (e.g. LED illuminants) the trailing edge dimmer has advantages.

For pure resistive loads (e.g. the light bulb), the type of dimmer does not matter.


The diagram shows on the X axis the sinusoidal half wave of the mains voltage divided into 16 equidistant time sections for leading / trailing edge.
According to the partial voltage supplied, the incandescent lamp extracts electrical power, which is why the dimming is suitable for saving energy.
On the Y axis, this is shown normalized with reference to the nominal power of the illuminant.

It can be seen that the correlation between the energy supplied and the radiated light is not linear, the light output decreases with dimming. Incidentally in the same context, the light color temperature drops.

That is, when dimming, the light of the incandescent lamp becomes more reddish and dark as energy is saved because it converts the greater part of the electrical power into heat.

The course of the light efficiancy and thus the brightness of a light bulb during dimming is the same for all incandescent lamps. That's why we never had to ask ourselves what the course was; It has always been determined by the simple physics of the tungsten filament.

Dimming of cold lamps

The correlation between the applied energy and the brightness of cold lamps (fluorescent tubes, energy saving lamps and LEDs) is determined by the electronic ballast. Since this can look totally different depending on the manufacturer, a cold lamp behaves correspondingly differently.

For this reason, there exists a distinction between dimmable and non-dimmable illuminants in contrast to the incandescent light bulb.
With the so-called dimmable LED lamps, however, the variance of the behavior during dimming as with light flickering has achieved such a degree that they largely do not correspond either to the behavior of a incandescent or to one another.

Or extremely: They call themselves dimmable, but sometimes they are not in practice, they may only survive operated on a dimmer.

In the meantime, it is generally known that a dimmer operated below its minimum load can cause problems, for example the light begins to flare like a candle light with low frequency and irregulary (not to be mixed up with light flicker at double mains frequency).
It is also known that the dimmability for other reasons fails with some dimmers and that there may be incompatibilities between dimmers and lamps.

This has also been stated by the NDR (a German radio broadcast service) in its program "Markt" series on 04-Apr-2016 (even if procedural errors were made, e.g. disregarding the dimmer minimum load).

However, this is not the subject of this page or of the dimming profile. The consideration of the minimum load and the basic compatibility of the dimmer with an LED illuminant is assumed for the following. Here with the dimmig profile it is about the illuminants unfortunate not ideal behaviour with an ideal dimmer, caused by the manufacturer's design of the electronic ballast.


The practice

By experience there are two main applications where the dimming behavior plays a role:

Application 1:

Many people replace a light bulb only with a defect against an LED illuminant. A mixing operation with LEDs is always possible without any technical problems.


However, if on dimmable chandelier you exchange the a candle incandescent bulb with an LED candle illuminant (same lumens and color temperature) the astonishment is perhaps big:




The LED illuminant dims differently, mostly it is significantly brighter than the light bulbs on the way to the dark.

Application 2:

In an existing apartment, all incandescents are exchanged for LED illuminants (no mixed operation):

Even if nothing flares or flickers, the LED bulbs can not be properly dimmed. Either the LED bulb is much too light (two to three times) when the dimmer is turned to the left. Or if at full brightness the dimmer is turned to the left to darken the light, nothing happens for long and suddenly within a small dimming range the light darkens much faster.

However, all this is not due to the dimmer but to the illuminant, which behaves completely differently under the same circumstances as the previously operated incandescent bulb.

The question of quantification

In contrast to light flickering, which can be dangerous or unhealthy, the dimming behavior of a luminous means is a pure quality feature and when dimming the illuminant, a lower quality is immediately noticeable to everyone.


This raises two questions about the problem:
1. How bright is the LED bulb in certain dimmer settings compared to an incandescent lamp?
2. How do you express the partial large differences between leading edge and trailing egde?


The consumer would therefore be much clearer if the dimming behavior of an illuminant is measured, set as a measure compared to an incandescent lamp and specified in the technical data.
I've been thinking about this for a long time and found a solution.


The answer

The reference dimmer is a specially developed ideal dimmer:
It is processor-controlled, operates precisely according to the (dimming) educational book, and is independent of the load in its behavior.
This means that the measuring method is independent of dimmers on the market, which in turn behave differently.

The measuring method only reflects the dimming behavior of the illuminant.


The dimming behavior is measured as a dimming profile (relative brightness vs. dim position) in 16 dimpositions (evenly distributed over 360° of a circle, i.e. at distances of 22.5°). By means of the positions 4... 14 used for a real dimmer, the associated dimming profile abberation is determined using the abbreviation DPA as a percentage.


Strictly speaking, two percentages are given because, in contrast to the incandescent bulb, it can make a very large difference whether the light source is dimmed with a classical leading edge or a more trailing edge dimmer. This also clearly indicates at which type of dimming the LED illuminant runs better.



In the following diagrams, the light bulb is designated "Incandescent" as the reference of the dimming profile, for the device unter test it is  "LE" for leading edge and "TE" for trailing edge.












Value range

Just as with light flickering: the smaller the deviation, the better.

The two figures as a pair of figures DPA/% = L##T## respectively indicate the percent deviations for leading edge and trailing edge.



With >99%, a lamp is not really dimmable in practice.

<= 25%

Values of <= 25% indicate that the light source can be adjusted properly.

<= 10%

At values of <= 10%, the illuminant is comparable with the behavior of incandescent lamps, that is, in mixed use, there will be hardly any difference noticable, with 0% there is no difference.














During the development of the DPA procedure I have noticed an additional horror:

It makes a difference with some lamps whether they are dimmed from light to dark or from dark to light (down-dimming or up-dimming):

For a particular dimming position (e.g. center), the brightness is different.

However, here the DPA specification no longer differentiates, all cases are measured, but only the more unfavorable is used as the final value.

Product assessment

Hereby I would like to clarify that the categorization and evaluation of the dimming properties of a product is not an overall assessment of the product but only the partial aspect of the dimming behavior. Nevertheless, I consider the DPA value to describe the dimming behavior for a useful quality criterion. Everyone makes their own decision, which criteria he or she uses to evaluate a product in its entirety.


The list on the test page for light flicker has already become very long.


From the presentation similar here the DPA list:

Brand Article Technique Socket Shape Lumens Watts DPA/%
Albrillo LL-LS19 LedM108dim R7s T-Roehre118 1000Lm 10W L14T15
Briloner 7233-018 LedM24dim 230V T-Dwn100W# 1000Lm 11W L23T13
Civilight CL8002W LedHdim 230V T-Dwn85W36 400Lm 6W L9T80
Civilight CL8134N LedHdim 230V T-Dwn85W36 400Lm 6W L9T80
Civilight CLE2428 LedF2dim E14 T-Kerze 300Lm 3W L15T85
Civilight CLE2432 LedF4dim E14 T-Kerze 450Lm 4W L15T53
Civilight Haled95-22164 LedHDim GU10 T-R50W36 345Lm 7W L13T--
DaylightItalia 700140-00A LedF2dim E27 T-Globe 250Lm 5W L13T21
Elinkume B35-600WLd LedF6dim E14 T-Kerze 600Lm 6W L8T13
Elinkume BF35-600WLd LedF6dim E14 T-Kerze 600Lm 6W L9T14
Elinkume G9-4Led20M-W5 LedF4dim G9 T-MiniBirne 226Lm 2W L8T15
Elinkume G9-HP14-W1-5114 LedM14dim G9 M-MiniBirne 220Lm 3W L7T15
Elinkume G9-T70D-W5 LedM70dim G9 T-MiniMais 420Lm 4W L11T16
euroLighting DMA5001-0523-01 LedM28Tldim 230V T-ChipR47 480Lm 6W L8T14
euroLighting DMA5001-1023-01 LedM28Tldim 230V T-ChipR47 900Lm 10W L>99T>99
euroLighting DMA5002-2023-01 LedM40Tldim 230V T-ChipR47 1700Lm 22W L8T13
FreLed F8-001-A30-7W LedMTldim 230V M-Dwn125W120 560Lm 7W L15T30
FreLed F8-001-A50-15W LedMTldim 230V M-Dwn180W120 1350Lm 15W L36T65
FreLed F8-001-A80-24W LedMTldim 230V M-Dwn230W120 2300Lm 24W L40T67
G-Glow E27-500WW1D LedF4dim E27 T-Birne 500Lm 5W L90T74
GaoTerLED GTL-C35-4A-dim LedF4dim E14 T-Kerze 360Lm 4W L19T27
GaoTerLED GTL-C35-6A-dim LedF6dim E14 T-Kerze 480Lm 5W L11T19
GaoTerLED GTL-A60-8A-dim LedF8dim E27 T-Birne 720Lm 6W L31T50
GaoTerLED GTL-G45-6A-dim LedF6dim E27 T-Tropfen 600Lm 5W L17T21
GreenAndCo FSL-GU10-7-30 LedHdim GU10 T-R50W36 500Lm 7W L18T11
GreenAndCo HAI-GU10-5W-Dim LedHdim GU10 T-R50W38 400Lm 5W L10T30
GreenAndCo HAI-GU10-7W-Dim LedHdim GU10 T-R50W38 530Lm 7W L13T28
GreenAndCo LL-C35-4W-E14-D-C LedF4dim E14 T-Kerze 470Lm 4W L13T20
GreenAndCo LL-ST64-7W-E27-D-A LedF4dim E27 T-Radio 638Lm 7W L16T31
GreenAndCo NZ-GU10-15SMD LedM15dim GU10 T-R50W110 400Lm 6W L18T44
GreenAndCo TM-A19-5W-E27-D LedF4dim E27 T-Birne 620Lm 5W L14T25
GreenAndCo TM-A19-8W-E27-D LedF8dim E27 T-Birne 960Lm 8W L19T32
GreenAndCo TM-A19-8W-E27-D-W LedF8dim E27 M-Birne 1000Lm 8W L28T43
GreenPowerLED LED1x6S10LD LedHdim GU10 T-R50W60 420Lm 6W L14T42
I-Glow 22134 LedF4dim E14 T-Kerze 470Lm 4W L46T77
I-Glow 22136 LedF4dim E27 T-Tropfen 470Lm 4W L48T75
Ikea LED1308G16 LedHdim E27 M-Globe 1000Lm 17W L6T24
Ikea LED1309G15 LedHdim E27 M-Birne 1000Lm 13W L39T69
Ikea LED1532R6 LedH5dim GU10 T-R50W36 400Lm 6W L10T18
Ikea LED1633G5 LedF4dim E27 T-Globe 400Lm 5W L7T11
lampsplus 960854 LedF4dim E27 T-Birne 750Lm 6W L12T15
Lansontech C35-Dim-Fl-E14-4W LedF4dim E14 T-Kerze 400Lm 4W L22T34
Lansontech C35-Dim-To-E14-4W LedF4dim E14 T-Kerze 400Lm 4W L21T32
Lctw 3004 LedHdim E14 T-Kerze 230Lm 5W L24T15
Lctw 4013 LedHdim E14 T-Kerze 470Lm 6W L29T31
Lctw 4031 LedHdim GU10 T-R50W36 345Lm 6W L21T22
LEDfux TREBR-738-WWS LedHTldim 230V T-Dwn86W38 430Lm 7W L7T9
Ledon 28000012 LedHdim E27 M-Birne 600Lm 10W L60T>99
Ledon 28000165 LedHdim E27 M-Birne 400Lm 7W L21T16
Ledon 28000239 LedHdim 230V T-R50W38 600Lm 10W L22T28
Ledon 28000289 LedHdim E27 M-Globe 800Lm 13W L18T11
Ledxon 9006063 LedHdim E27 M-Birne 806Lm 10W L23T49
LivarnoLux HG00785C LedHdim E14 M-Kerze 470Lm 6W L15T60
LivarnoLux HG00785D LedHdim E27 M-Birne 470Lm 7W L12T62
Luxon YHDE-1001-004 LedF6dim E27 T-Birne 550Lm 6W L11T13
Megos MELED400-15WBD LedHdim E27 M-Birne 1500Lm 15W L23T50
Megos MELED400-5WMB-E14D LedHdim E14 M-Tropfen 470Lm 5W L20T61
Megos MELED400-9WBD LedHdim E27 M-Birne 806Lm 9W L26T70
Mueller 43084 LedF4dim E14 T-Kerze 430Lm 4W L25T60
Mueller 43179 LedHdim E14 M-R50 470Lm 6W L16T26
Mueller 43182 LedH9dim GU10 T-R50W36 400Lm 6W L22T29
Neverland D094-C16W LedF6dim E14 T-Kerze 600Lm 6W L12T15
OakLeaf 101047UK LedF4dim E27 T-Radio 330Lm 4W L14T22
Osram LPPAR16D5036 LedHdim GU10 T-R50W36 350Lm 5W L42T91
Osram PCLB25ADV-4W-82 LedHdim E14 M-Kerze 250Lm 5W L23T14
Osram RF-GLOBE-54-7W-824-E27-FIL LedF4dim E27 T-Globe 710Lm 7W L42T67
Osram SSTCLA75D10W-82 LedHdim E27 M-Birne 1055Lm 10W L24T43
Osram SSTLINE125-15W827-R7s LedM96dim R7s T-Roehre118 2000Lm 15W L10T11
Osram SSTLINE75-8W827-R7s LedM64dim R7s T-Roehre78 1055Lm 8W L8T13
PbVersand 360-G9COB LedHdim G9 T-MiniBirne 200Lm 2W L9T14
Philips 8718696438305 LedHdim GU10 T-R50W40 280Lm 4W L28T35
Philips 8718696457177 LedHdim GU10 T-R50W40 378Lm 6W L10T17
Philips 8718696481202 LedHdim E27 T-Birne 470Lm 6W L11T16
Philips 8718696575475 LedF6dim E27 T-Birne 806Lm 8W L7T25
Philips 8718696578735 LedM48dim R7s T-Roehre118 1600Lm 14W L7T26
Philips 8718696713464 LedM72dim R7s T-Roehre118 2000Lm 14W L19T45
Philips 929000186702 LedHdim E14 T-Kerze 136Lm 3W L6T46
Philips 9290012211 LedHdim GU10 T-R50W36 245Lm 5W L8T32
Rewe 3014176 LedHdim E27 M-Birne 806Lm 9W L18T45
Rewe 3014182 LedHdim E27 M-Birne 1055Lm 11W L16T37
Rewe 3014186 LedHdim E14 M-Tropfen 470Lm 6W L27T60
Rewe 3014190 LedHdim E14 M-Kerze 470Lm 6W L28T58
Rossmann Rubin-13842 LedH4dim GU10 T-R50W32 350Lm 5W L53T>99
S7Seven XXX1 LedF6dim E14 T-Kerze 600Lm 6W L9T11
S7Seven XXX2 LedF6dim E14 T-Kerze 600Lm 6W L9T12
S7Seven XXXX LedF6dim E27 T-Roehre 600Lm 6W L8T16
Segula 50295 LedF4dim E27 T-Radio 400Lm 6W L19T21
Segula 50500 LedF4dim E27 T-Radio 250Lm 6W L17T20
Sigor 6118001 LedF4dim E27 T-Birne 400Lm 4W L43T>99
Sunmeg St64-8W LedF6dim E27 T-Radio 500Lm 8W L12T11
Tala GAIA-6W-2200K-E27-NT LedF8dim E27 T-Birne 480Lm 6W L15T26
Tamaykim E146W27 LedF6dim E14 T-Kerze 600Lm 6W L8T12
Tamaykim G9-5W30 LedM45dim G9 T-MiniMais 450Lm 5W L10T11
Toshiba LDAC0627E7EUD LedHdim E27 M-Birne 325Lm 6W L33T77
Toshiba LDCC0627FE4EUD LedHdim E14 M-Kerze 250Lm 6W L38T85
True-Light 8012 LedHdim E27 M-Birne 970Lm 12W L8T8
Unqi C35T4WE14Dim LedF4dim E14 T-Kerze 400Lm 4W L95T>99
Unqi XXXX LedF4dim E27 T-Tropfen 400Lm 4W L23T26
X Gluehbirne IncHalo E27 T-Birne 700Lm 42W L0T0
X Gluehbirne IncHalodim MR11 T-R35W35 400Lm 20W L1T1
X Gluehbirne IncStddim E14 T-MiniBirne 110Lm 25W L2T0


It should be noted that, particularly some filament lamps and all driverless lamps, which each contain only a small amount of electronics, perform relatively well in the dimming behavior, which is similar to the tungsten filament in the nature of the (missing) thing. However, these lamps have very high light flicker values, so a view at the light flicker test page is quite important.