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Dimming LED Lamps

September 24, 2010   

Dimming LED lamps is nowhere near as simple as halogen lamps where a simple change in the voltage will provide smooth dimming. LED

September 26, 2012 at 5:16 am

i am installing 16 dimmable gu10 led lamps probably between 4 and9 watt each 8 is dimmed of 1 dimmer and other 8 of another dimmer. what dimer switch will i need.i am led to beleive that i need trailing edge dimmers, is this true.many thanks steve.

David Wells
October 28, 2012 at 10:40 am

I’ve just bought a set of dimmable LEDs and an inteligent LED dimmer switch. the total wattage from the 7 LEDs is 42w. On testing I find that the light output (520 lumens each) is barely acceptable and i would never dim these. Can I use these with a normal (non dimmer) switch?

Jason Churchill
June 16, 2013 at 2:50 am

What would be the outcome of putting a leading edge 5w bulb through a trailing edge system and vis versa

June 26, 2013 at 10:47 am

Hi Jason,

As you probably know phase cutting technology works by cutting off part of the mains voltage to vary the RMS voltage fed to the lamp. The brightness of the lamps is then controlled by increasing or decresaing the RMS and so the power supplied to it.

There are two ways of doing this , at the beginnng of the sine wave or at the end, If it is done at the beginning it is called leading edge, and after is called trailing edge. I have never tried your application but I would guess the may be a flicker effect in the lamp through its dimming range, how is the system you have trailing edge?


July 20, 2013 at 1:31 am

I have just enstalled some led dimmable lights and they are too bright even at the lowest setting. What can I do?

July 23, 2013 at 1:15 pm

Hi Marge,

A good dimmer should dim the LED’s to a very low light, perhaps there is a problem with the dimmer not compatible with the lamps?
Let me know what Lamps and dimmer you have a we will try to sort the problem out for you.

Darren Sprawson
November 7, 2014 at 2:12 pm

I have a “1 way 230v AC Remote/Touch Control Intelligent Dimmer switch, max 400w- min 40w”, to operate a 4 lamp ceiling fitting. Unfortunately, it only turns on and off, I’m using 4 Philips 4W Master Dimmable GU10 LED – Warm White (25

November 7, 2014 at 2:22 pm

Hi Darren,
The dimmer low operating level is too high for your 4 x 4w lamps, the dimmer operates from 40w, you only have 16w in LED Lamps so the current requirement won’t make the dimming circuit switch and operate. In a way the circuit cannot detect the load. You can either increase the load to over 40w or get a new dimmer that operates at a much lower level. There are many designed to start from a 5w load. You may be able to purchase a Resload (dummy load), but it may have to be matched to the dimmer, check with the manufacturer. I hope this helps?

john barber
November 10, 2014 at 12:19 pm

I have Varilight dimmers in all the rooms in my house. I have started to replace the bulbs with LEDs. I have recently replaced the first circuit using 3 GU10 COB LED bulbs, but I find the dimming range is not great, resulting in not being able to dim to the level I would like. Is this because the dimmer is leading edge type, and if so is my only course of action to replace all my (expensive) dimmers? Thank you

November 13, 2014 at 2:41 pm

Hi John,

Trailing edge are preferred, what is the stated range on the dimming specification for the dimmers you have, for example, 5w-250w etc…

January 16, 2015 at 7:03 pm

I wish to buy a good dimmer to give me a wide range of dimming when controlling 5 x 5w GU10 LED bulbs (Screwfix 3797g), please advise.

January 17, 2015 at 11:25 am

Hi Mike, We can recemmend the Varilight J series as a reliable dimmer which can be purchased on line from reputable retailers.


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