How to dim LED’s correctly

A common problem both electricians and home users come across while using LED’s is How to dim LED’s correctly so that they do not flicker or damage the transformer or LED’s themselves.

As i’m sure you know dear reader LED lighting has become the most popular way to illuminate our lives, be it at home or in work place or even on our streets and highways, LED lighting brings many benefits to the table with longer lifespans, less energy used, more environmentally friendly than the traditional lighting sources, and a great way of saving money to boot.

With all these advantages the LED’s bring to us there has been one problem home users and electricians have come across is how to dim LED’s correctly so as not to damage any of the equipment including the LED’s themselves, and to also stop the LED’s flickering when lowering the power. Let’s take a look at the solution to correctly dim them.

The Traditional Way

Resistive Dimming

Resistive Dimming is the standard way of dimming halogen lighting which works by reducing the voltage allowed to the bulb with a variable resistor. How this works is by the resistive dimmer switch being installed simply by wiring between the mains (240V) power and the bulb, the light is then dimmed but the voltage resistance is converted to heat which means it is not energy efficient.

Unfortunately with this method of dimming light it is not possible to use with LED lighting as LED’s use between 12V to 48V, so a transformer sits between the power and the LED’s to convert the mains power (110V-240V) to the required voltage needed for the LED’s. With this in mind using a resistive dimmer between the main voltage and the transformer would in fact  damage the transformer, and if you were to put the resistive dimmer between the transformer and the LED’s it would cause them to flicker and will slowly damage the LED’s.

The Correct Options

Triac Dimming 

The Triac (Triode for Alternating Current) dimmer is one way of dimming LED’s, it works by conducting the current both directions by alternating at variable speeds. What this achieves is the light emitted from the LED’s looks steady but in actual fact the light is flickering at a very high speed that the human eye cannot pick up on it. In order for the Triac dimmer to achieve this it requires a signal to tell the dimmer how much it needs to dim the LED’s, so to achieve this another module is required to sit next to it,  an 0-10v dimming module.

0-10v Dimming

The 0-10v signals work by sending a separate 10 volt signal to the Triac module and then uses a resistive dimmer to reduce the voltage on the 10 volt signal. The voltage then drops and the dimmer module then reduces the brightness of the LED light in relation to the current voltage.

Here is an example
10V = Dim at 100%
8V = Dim at 80%
3V =Dim at 30%

Dali Dimming

Another option to achieve the dimming of LED’s is Dali. Dali is an open source 2-way protocol which is designed to control lighting in the home, which is royalty free standard which allows it to be possible to mix and match Dali modules. The Dali module works by assigning zones and linking all the DALI modules for each zone together. The Dali controller can then control multiple zones individually.

DMX Dimming

The final option for dimming is the DMX dimming protocol. The DMX 512 protocol was originally designed to control nightclub and theatre lighting and has recently started to be used in home lighting.

DMX works by sending a data signal which has a value between 0 and 255 on each channel with a maximum number of channels being 512. The signals carry the information for all the channels to each dimmer module receiving the DMX.

What this means is that each of the dimmer modules is given a DMX address so it knows which channel to read and adjust the brightness accordingly. Each dimmer module has an DMX in and an DMX out socket so that the data is allowed to flow around the system in a daisy chain effect from one module to the next. The DMX can control colour changing lighting as well as non lighting devices such as fog machines and blinds.


These are the correct three options you have for dimming LED lights, so it is important to decide which way is best for your project needs. Here at InStyle LED we have you covered with all options available in stock and our friendly sales staff can advice you on which set up is best for you.

You can call InStyle LED Ltd on 0116 2799 083 or email us at [email protected]