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Dimming LEDs: what you need to know

Dimmable light brings flexibility and creates atmosphere. In addition, dimming lighting can save energy. While LED lamps are on the rise in terms of power savings and sustainability, they lose out to conventional halogen or incandescent lamps when it comes to dimmability.
Learn everything you need to know about dimming LED lamps here.

LEDs: How they work

To understand the difficulties of dimming LED lamps, it is important to understand how they work. LED lamps use semiconductor chips that move electrons through a semiconductor crystal to produce light. Unlike incandescent lamps, which produce light by burning through a tungsten filament, LED lamps require a constant power supply to operate.

Therefore, while dimming incandescent or halogen lamps simply works by reducing voltage, dimming or brightening light-emitting diodes is a bit more difficult. Basically, it is not the LED lamp itself that is dimmed, but the intermediate electronics that convert the AC voltage from the mains into DC voltage.

How can LED lamps be dimmed?

There are several ways to dim LED lamps, including

1. LED dimmer

An LED dimmer is a device designed specifically for LED lamps that adjusts the brightness of the light by changing the voltage or current. Some LED dimmers require special wiring, while others can be installed directly into existing wiring. 

2. phase cut dimmer

A phase cut dimmer is a device that reduces power by reducing the current in a sine wave cycle. It is important to note that not all LED lamps are compatible with a phase cut dimmer. Make sure you choose a model that is specifically designed for use with LED lamps.

3. PWM dimmer

A PWM dimmer uses pulse width modulation to regulate the brightness of LED lamps. It is especially effective in regulating the brightness of RGB LED lamps because it provides the ability to change the color of the light. 

4. DALI interface

Through a so-called "digital addressable lighting interface", LED lamps can be networked, controlled and also dimmed. In the process, sequences can be programmed via a DALI interface in a similar way to smart lighting, or luminaires can be combined into groups. However, so far only a few LED luminaires are compatible with DALI dimmers. So be sure to check whether your new lighting is suitable for the popular DALI technology.

Dimming LEDs: these 10 points to keep in mind

When dimming LED lights, there are a few factors you should consider to ensure,
that everything works flicker-free and safely:

1. compatibility of dimmers and LED lamps:

LED lamps require special dimmers to be dimmed properly. It is important to ensure that the dimmer and LED lamp are compatible to avoid flicker, hum or damage. 

2. The right power supply:

If you decide to adjust the power supply of the LED lamps to dim them, you should make sure that the voltage and current of the power supply are correct to ensure proper operation. Some LED lamps may also need a special driver to be dimmed properly. 

3. LED lamps are not all the same:

Not all LED lamps are the same. Some can be dimmed better than others. It is important to make sure that the LED lamp you want to use is suitable for dimming. 

4. Maximum dimming level:

LED lamps have a maximum dimming level, which may vary depending on the model. It is important to know the maximum dimming level of LED lamps and not dim them too far to ensure proper operation. 

5. Impact on Lifetime:

Dimming LED lamps can affect their lifespan. Poor dimming can cause the lamp to fail sooner than expected. It is important to be careful not to overheat or overload the LED lamp to ensure a longer life.

6. color temperature and brightness:

When dimming LED lamps, the color temperature may also change. For example, some LED lamps can have a yellow cast when dimmed. It is important to consider this if you want to create the desired atmosphere in the room. Also, make sure that the brightness is not reduced too much to ensure a comfortable room light. 

7. number of lamps:

If you want to dim several LED lamps at the same time, it is important to make sure that they are all compatible and that the dimmer has enough power to dim all the lamps. Otherwise, it may cause flickering or overload. 

8. dimming colored LED lamps:

Colored LED lamps can also be dimmed, but it is important that the dimmer is suitable for the color temperature of the LED lamp. Otherwise, it may cause color shift. 

9. use of intelligent lighting systems:

Smart lighting systems can automate the dimming of LED lamps and make it easier to create the desired atmosphere in the room. However, it is important to make sure that the LED lamps and dimmer are compatible with the smart lighting system. 

10. Safety:

It is important to pay attention to safety when dimming LED lamps. Make sure that the appropriate dimmer is properly installed and that all cables and connections are functional and correctly mounted.

Successful dimming of LED lamps at a glance

  • Use only LED light sources that are explicitly marked as dimmable 
  • Note the compatibility of the LED technology and the dimmer technology (compare letters L or C) 
  • The power of the LED lamps must be within the load range of the dimmer (observe minimum load & maximum load)

LED dimmer: different types

Lighting dimming can be accomplished in a number of ways. Basically, there are two types of dimmers: 

  • Flush-mounted dimmers are often used for general lighting and are inserted into the flush-mounted box instead of the light switch 
  • Cord dimmers are often found in table or floor lamps. The dimmer is placed in the supply line than on the cable of the luminaire.

Touch dimmers enable switching and dimming of the light via the light switch. Depending on the touch dimmer, preset levels can be set or the light is dimmed steplessly depending on the button press length. 

Rotary dimmers control dimming steplessly via a rotary wheel. Switching on and off is made possible by pressing this wheel. Touch dimmers are switches built into the wall, with the help of which the light is controlled. Short touch switches the lighting, longer contact with the touch switch allows stepless dimming. 

Radio dimmers work by means of remote control Depending on the model, this opens up countless different possibilities for light control.

Save energy with dimmed LED lighting

Dimming LEDs brings numerous benefits in addition to flexibility in terms of illuminance:

Energy Savings 
One of the main benefits of LED dimmers is energy savings. By reducing the brightness, you can lower energy consumption and, in turn, your electric bill. LEDs are already energy efficient, but dimming gives you additional control over energy consumption.

Customizable lighting
LED dimmers offer the ability to customize lighting. You can increase or decrease the brightness as needed. This allows for more flexibility in creating the ambiance of the room and creates a pleasant atmosphere.
Longer life of LED lights
Dimming LEDs can also extend the life of LED lights. Reducing the brightness reduces the amount of heat generated, which results in less stress on the LEDs. This allows the LEDs to last longer and saves you the cost of replacing bulbs in the long run.

Dimming with Smart Lighting

Smart home products are enjoying growing popularity. Smart lighting is easily controlled via smartphone or tablet. In addition to the brightness, the color temperature can also be set as desired and individual light scenes can be defined.

Tip: Human Centric Lighting (HCL) controls the light according to the natural course of the sun. This means that light intensity and color temperature are constantly adjusted throughout the day. HCL thus ideally supports the human biorhythm and promotes concentration, motivation and performance.

Problems with dimming LED lamps

Since dimming LED lamps is technically more complicated than adjusting the brightness of conventional halogen
or incandescent lamps, undesirable difficulties often arise:

The LED light flickers 

If the light flickers when dimmed, an incorrect dimmer is often the cause. Since there are no uniform standards, incompatibilities often result in the dimmer's uptake load being significantly undercut and the lamp flickering. 

The LED lamp cannot be dimmed or does not light up 

There are two reasons why the lamp cannot be dimmed or it has run out of light:

1. the LED lamp is not dimmable (be sure to look for an appropriate label when purchasing). 

2. the minimum load of the dimmer is not reached with the LED lamps used.

Humming dimmer 

If the dimmer makes humming noises, this is usually due to an incompatibility between the dimmer and the control gear. In this case, it is essential to make sure that the dimmer and ballast are marked with the same letter (L or C). In addition, poor quality can lead to unpleasant noises on the part of the dimmer. Inferior products tend to overheat due to inadequate heat dissipation. This can also cause a humming noise. 

LED lamp glows after 

If the light continues to glow after it has been switched off, this can have several causes. Often it is residual energy from the operating device. However, if the light does not go out completely, the dimmer can also be the cause of the problem. Its minimum load is then not reached. In this case, a dimmer designed for the LED lamp provides a remedy.

FAQ about dimmable LED lamps

Can all LEDs be dimmed?

Not all LED lamps are dimmable. They must be explicitly marked as dimmable (packaging / technical data), otherwise you risk irreparable damage to your lamp.

How do I recognize dimmable LED lamps?

You can often recognize dimmable LED lamps by a corresponding note on the packaging or in the technical data of the lamps. In our store you can also use the practical filter to find dimmable LED lamps.

How do I find the right dimmer?

Dimmer and LED light source must be compatible with each other. In addition, the minimum load of the dimmer must be observed and the maximum load must not be exceeded.