Have you tried to dip an LED bulb and you only got flickering and buzzing? If you have happened to you and want to understand how it is possible to connect the LED bulbs to the Dimmer, to vary the brightness, you are reading the right article!
In this article we talk about LED bulbs that operate at 230V mains voltage in alternating. If you want to reduce the brightness of LED lamps powered by direct current, low voltage for automotive use, I talked about it at the bottom of this article.
I recommend, When you put your hand to the electrical system, you have to remove tension from the magnetothermal and, possibly, get help from qualified personnel!
What is the advantage of dimmable LED lamps over incandescent ones?
LED bulbs offer several advantages compared to traditional incandescent, halogen and cfl. In this paragraph we analyze some advantages, but ... be careful! All that glitters is not gold!
A dimmable LED bulb does not change the color when it reduces light intensity. On the contrary, an incandescent lamp tends to become more yellow as the brightness is reduced.
An LED lamp consumes less current: generally the ratio is 1/6 - 1/8 compared to an incandescent bulbs of equivalent light performance. Compared to CFL fluorescent bulbs, consumption is lower, but the relationship is not so interesting.
By consuming less current, the LED bulb heats up less, but don't be fooled! LEDs also have a much lower tolerance to heat than traditional light bulbs. If you want to dip an LED bulb, so that it lasts as long as possible, it must be able to dissipate heat. If it is installed in a small, completely closed chandelier, your LED bulb will last very little.
The LED bulbs, if they are of a good brand, last more spite of incandescent bulbs and fluorescent cfl. Manufacturers declare that LEDs last 10 times more than incandescent lamps, but, also in this case, don't be fooled! The LED can last a lot, but ... the power supply inside the light bulb is always the first component to damage! In particular, it is damaged with heat. Therefore, it is true that LED bulbs last more than traditional ones, if of good brand, but do not last long when it is declared.
How to connect an LED bulb to the dimmer?
Let's start right away with the bad news! LED bulbs, in general, are not dimmable! To reduce the brightness of LED bulbs, you have to buy prepared lamps.
I will write another article related to how to choose the best LED bulb for your needs. In this article I dwell on dimmability.
There are three types of dimmable LED bulbs:
- step dimmable LED bulbs;
- LED bulbs that can be connected to dimmers;
- LED bulbs with external power supply.
It is not possible to understand, from the shape, if an LED bulb is dimmable. To check if a light bulb is dimmable, one of these symbols must be searched (on the box, on the light bulb or in the description of the object when you buy it).
The most left symbol indicates that the bulb is not dimmable. The icon in the center indicates that it is dimmable to step (but cannot be connected to the dimmer). The symbol on the right indicates a light bulb that can be connected to the dimmer and that can vary the light intensity continuously.
LED bulbs Dimmerible in Step
A step dimmable LED bulb (usually three steps), cannot be connected to the dimmer.
It replaces a traditional incandescent bulb and, every time it is turned off and on again, the brightness changes: low brightness, medium intensity and full brightness.
It is a good solution if the home electrical system is not equipped with a dimmer to vary the brightness with continuous adjustment.
Dimming an LED bulb (with the dimmer)
If the electrical system of the home is equipped with a dimmer, you can buy led bulbs in accordance with continuously.
LED bulbs are entirely a substitute for incandescent bulbs, both in shape and attack.
To dip an LED bulb, the choice must fall on a good brand bulb, dimmable continuously.
I recommend, before buying all the home bulbs of the same type, to try one! In fact, some dimmable LED bulbs tend to have a annoying stroboscope effect. With bulbs with this defect, moving objects seem to move to small shots. The effect is most visible at night, when there are no other environmental lighting sources.
Adjustments on the dimmer to reduce flickering and hum
Before turning on the LED bulb with the dimmer, try to check if your dimmer is settable. On some dimmers there are trimmers and adjustment selectors.
If the flicker led bulb, especially with a very low brightness, it is good to set the dimmer with a slightly higher brightness, so as not to make the LED flicker.
In addition, I recommend setting the dimmer (if it presents this possibility) on halogen (or incandescent) bulb. By setting the dimmer to other modes (e.g. fluorescent lamps or transformers), LED bulbs may emit loud buzzes and flicker, especially when the brightness is decreased.
If your Dimmer provides for the possibility to regulate even the maximum brightness, I recommend not to exceed 80%. By setting the maximum brightness of the Dimmer at 80%, instead of 100%, the duration of the light bulb will increase definitely.
Dimmable LED bulbs, with external power supply
There are LED lamps that operate at low voltage and are equipped with a separate power supply (driver).
To tell this type of bulbs, it must be verified that the power supply is prepared to vary the brightness. If it weren't, you have to buy a power supply with adjustable exit. Obviously the characteristics of the new power supply must be identical to the old. In particular, I refer to the LED current (which must never be higher than that of the previous power supply) and the tension.
There are adjustable power supplies, which can be adapted to different types of LED lamps.
The new power supply must be prepared to vary the outgoing current. In particular, you can opt for a power supply that has an entrance with potentiometer or with a 0-10v input to be connected to the home automation system, if your home is equipped with it.
Or, the power supply could already have an entrance compatible with the protocol that is used in the home automation system, for example Konnex Knx, Control Casa or Dali.
If the LED bulbs always stay on?
It can happen that, when the dimmer is off, some LED bulbs still remain on! This situation happens because some dimmers still need a minimum output load and the LEDs, when adjusted at low brightness, have an absorption of less than the minimum.
In this case, to leave the LED bulbs off when the dimmer is turned off, We must install, in parallel at the exit of the dimmer (or, equivalently, in parallel to the LED bulb) a suitably calculated resistance, to simulate the absorption of a small load.
The resistance must be of power, at least 3W, Of 47000ohm - 68000ohm, which ensures minimal absorption when the dimmer is turned off. If only one resistor is not able to solve the problem, you can try to parallel two resistors, or to use one from 22000ohm, 5W of power. Among the various resistance options available, you have to choose a model that resists high voltages. The 230V alternating mains voltage has peaks of over 330V peak. Therefore the choice must fall on a resistor that can accept voltages of at least 350V (generally they are from 500V).
The alternative, if the chandelier is equipped with multiple bulbs, could be to leave an incandescent bulb between the various LED bulbs. This alternative, although faster to practice, is however less pleasant aesthetically.
Very useful article. Some things I already knew, but I didn't know about resistance.
Thanks so much!
I purchased dimmable LED bulbs with R7S socket to replace halogen
and their behavior is affected by the type of feeding.
1) Single bulb driven by simple switch: everything ok
2) Single bulb driven by dimmer (Ticino from apartment, I do not think settable): everything ok.
3) Two bulbs driven by a dimmer:
a) both installed: heavy flickering and at maximum brightness they turn off
b) only one installed and the other empty lamp: as above
c) an installed and the other lamp holder with the old halogen: everything ok
Electrotechnically speaking I don't explain it so much, but I think I have a speech
Like the one addressed by talking about the resistance.
If with the halogen lamp in parallel to the LED one everything works, it is certainly a minimum load issue. At this point, either replace the dimmer (with one prepared for LED lamps) or install the parallel resistance. Take into account, as explained in the article, that the resistance can heat and is powered by high voltage.