Everything you need to know about dimmers – Full Guide [2020], Part 1 – Qubino
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Everything you need to know about dimmers – Full Guide [2020], Part 1

The times when the lights were used only to illuminate the space are far gone. With dimmers and new lighting solutions coming to the market and with the different options that it brings, adjusting lighting to create a relaxing and comfortable atmosphere, is becoming a must in every modern home.

Even though making your lights dimmable is quite easy, there are still a few problems and questions people have before deciding to do that.

Which light bulb should I choose? What is the difference between dimmable and non-dimmable ones? What is a dimmer? Is it possible to dim a non-dimmable bulb? What about when it is connected to a dimmer switch? Why is the bulb buzzing and flickering?

In this article, we’ve prepared an overview of information, tips, and answers that you need, in order to avoid issues along the way and make your dimming project a success.

Dimmability –

What does it mean and why did we invent dimmers?

Ability to be dimmed – able to have illumination decreased in brightness.

Long ago, when only traditional incandescent bulbs were available on the market, dimmers were introduced in order to decrease the power consumption of the light source, thus a decrease of the monthly electrical bill. These times are now gone and honestly speaking, by introducing the LED light bulbs as the main light source, the feature of the dimmer decreasing the power consumption is no longer perceived as a single purpose functionality.

What dimmers are?

As introduced in the previous chapter, dimmers are devices that are used to adjust the amount of light. Usually, this adjustment is done by changing/altering the supply voltage waveform to the lamp. By doing so, the light intensity will decrease as well as the power consumption which leads to fewer costs. Another benefit of dimming down the light is increasing its life-time means fewer lamp replacements and so maintenance costs. Besides cutting down costs – something you can count on, there are other priceless benefits. Check out the 2nd part of the blog, about smart dimmers

What kind of dimmers do we know?

There are different types of dimmers that one can find on the market:

  • Analogue – the lighting is controlled in analog and not digital (bits) manner.
    • Phase dimming by alternating the supply voltage
      • Leading-edge
      • Trailing edge
    • 1 – 10 Vdc regulation
    • Touch
  • Digital – the lighting is controlled in a digital way, where the dimming signal is transformed into bits.
    • DALI

Dimmable vs. non-dimmable light bulbs

Before getting to the point of dimmable and non-dimmable light bulbs it is good to think about how you’re going to use your lights. Do you want to control them by dimming the brightness from min to max level or do you only need them to switch on and off?

In case you need your light only to go on or off, you can use a dimmable or non-dimmable bulb. But if you want to dim it, then only a dimmable bulb can be used. It is good to add, that some bulbs we’ve tested, even being rated as non-dimmable, were able to take the dimming function. Nevertheless, do not be fooled by this information as we’ve only tested this for our purposes as myth breaking. You should always stick to the facts written by bulb manufacturers.

Dimmable bulbs

Dimmers icon. The picture is showing the icon for dimming. One side - other + and the arc between them.

By changing/altering the supply voltage waveform to the lamp, we’re changing its power output or brightness – this is called dimming.

The most common bulbs, that can be dimmed are:

  • Incandescent and halogen light bulbs
  • Fluorescent light bulbs are known also as CFL
  • LED light bulbs

Basically, all incandescent and halogen lights can be dimmed. Thus, this is not always the case when speaking about other technologies as LED, CFL, etc. Moreover, LED and CFL lights have in majority lower dimming range compared to filament ones. A quality LED or CFL lamp may support dimming down to about 10-15 % of total output power. On the other hand, filament bulbs can go down to about 1-2 %.

Long story short, the dimming range you might get on a light bulb depends on at least three things:

  • electric system (3 or 2-wire installation, this means with or without neutral wire)
  • bulb type (incandescent, halogen, LED, CFL)
  • dimmer module

A dimmable bulb can either work as a dimmer, in dimming mode, or as a normal switch, in ON/OFF mode. It perfectly fits both use cases.

Step dimmable bulbs

Dimmers icon. The picture is showing the icon for 3 step dimming. One side - other + and the arc between them. Between the start and the end of the arc are free two free spaces.

Nowadays, it is quite common to find 3-step dimmable bulbs on the market. In most cases, the available dimming range is 10, 50, and 100%. The whole story about these bulbs is actually very simple. Just replace your existing, non-dimmable bulb, with this one and you’re done. You only need to push the switch button ON and the light itself turns to example 100% of its brightness. The next OFF/ON turns the light to 50% of its brightness, etc. Besides the light bulb, nothing else needs to change.


Non-dimmable bulbs

Dimmers icon. The picture is showing a non-dimmable icon. One side - other + and the arc between them. The picture is in the circle and has a cross on it.

With a non-dimmable bulb, decreasing and increasing brightness is not recommended, allowed, or even is not possible.

Nevertheless, in combination with a dimmer in dimming or ON/OFF mode, this bulb can work, with certain limitations. The limitation is that when the dimmer is in dimming mode, the bulb must always get 100% of the power supply, which is basically the same as you get when you put ON in ON/OFF mode.

Here are two common use cases when this could be useful:

  • It is Sunday afternoon; everything is closed, and your kitchen dimmable light bulb fails. As a replacement, you only have some old, non-dimmable bulbs available. You can simply exchange the failed dimmable bulb with the working non-dimmable and set the dimmer’s brightness level up to 100%.
  • You’re passing to home automation, but the entire house is running on non-dimmable bulbs. It would be non-sense throwing away fully functional bulbs. Therefore, you can install dimmers, where needed, and use the ON/OFF mode till the non-dimmable light bulb fails or you simply decide that you had enough waiting.

FAQ for dimmers and dimmable lights:

How do I know if a light bulb is dimmable or not?
You should check the markings on the light bulb packaging. If there is a crossed dimming curve, the light is not supposed to be dimmed.

Can I replace a dimmable bulb with a non-dimmable light bulb?
Yes, you can, but you need to pay extra attention. The non-dimmable bulb should only work when it has 100% voltage.

Can I replace non-dimmable with dimmable light bulbs?
No problem, just go for it. The only drawback of this installation is that you’re not using the main functionality of the dimmable bulb – dimming (unless you buy a step dimmable one). In a  system, where you previously had a non-dimmable bulb, there is lacking a circuit that is able to dim the new dimmable bulb.

Can I dim a non-dimmable light bulb?
If you’re installing a non-dimmable light bulb into a dimmable system, it will probably work when the dimmer is set to maximum power, so to 100%. Dimming a non-dimmable light bulb may be noticed as a strange working behavior of the dimmer and/or light bulb. Flickering and/or buzzing may be present and eventually one of the two may fail.

To sum up about dimmers and dimmability

  1. Never connect loads to the dimmer, exceeding minimum or maximum power limit. This might lead to dangerous situations and failures.
  2. Do not connect different types of light bulbs or drivers simultaneously. These may act differently from one to the other causing instabilities and/or failures.
  3. When connecting LED drivers to dimmers, make sure that the driver itself is dimmable. If you only have the LED light dimmable, it doesn’t mean you can dim the driver as well.
  4. Do not dim a dimmer with another dimmer. In the best case, only one will fail.

Now that you are well-equipped with the knowledge regarding dimmers and different types of bulbs, stay tuned for the second part of the article, in which we will take you one step forward and introduce you how you can make your lights not only dimmable but also smart by using a smart dimmer.