Dimming an LED lamp seems simple, until the lamp flickers, hums or no longer switches off. That is almost always because the lamp and the dimmer don’t match. In this guide I explain what a dimmable LED lamp is, which LED dimmer you need and what to do if your dimmer doesn’t work.
In short
- Dimmable? You can only dim lamps that are marked as dimmable. A standard LED on a dimmer flickers or breaks.
- Dimmer: choose a dimmer made for LED, preferably a universal LED dimmer with trailing-edge dimming.
- Minimum load: LED uses little power. A single 5-watt lamp is too little for many dimmers.
- Test: buy one lamp first and try it before you replace the whole house.
Jump straight to:
What is a dimmable LED lamp?
With an incandescent bulb the dimmer simply regulates the voltage. An LED lamp has electronics (a driver) that convert the current, and these must be able to process the dimming signal. Only a dimmable LED lamp can do that. You can tell by the word dimmable or dimmable on the packaging or in the product description. A lamp without that label can’t be dimmed: it flickers, hums or breaks after a short time.
Dimmable by type of lighting
Spots and lamps: check whether GU10, E27 or E14 is marked as dimmable. Take a look at our LED spots. LED strips: you dim via the power supply or a separate strip dimmer, see LED strips. Panels: only panels with a dimmable driver, see LED panels and downlights.
Smart dimming without a wall dimmer
You dim smart lamps with an app, voice or remote control. Then you don’t need a separate dimmer in the wall, and so no compatibility problems either. Do always leave the light switch on. Take a look at the LED wifi lighting.
Choosing the right LED dimmer
A dimmer from the incandescent era is usually not suitable for LED. Pay attention to these three points.
Leading edge or trailing edge
A dimmer chops a piece off the sine wave. With leading-edge dimming this happens at the start, with trailing-edge dimming at the end. Most LED lamps dim more smoothly with trailing edge. A universal LED dimmer can do both and picks the best setting itself. You can find more terms in the LED alphabet.
Minimum and maximum load
Every dimmer has a minimum and a maximum power. An old dimmer of 40 to 400 watts doesn’t work with a single 5-watt LED, because that is below the minimum. Choose an LED dimmer with a low minimum (for example from 3 watts) and add up the total power of all the lamps. Stay well below the maximum, because the inrush current of LED lamps is higher than their wattage suggests.
Dimming LED strips
You don’t dim an LED strip on 12 or 24 volts with an ordinary wall dimmer. You use a PWM dimmer between the power supply and the strip, or a dimmable power supply. The dimmer must handle the same voltage and enough amps. You can read ideas for atmosphere in Indirect lighting with LED strips.
Several lamps on one dimmer
On one dimmer, preferably use lamps of the same brand and type. Different drivers react differently, so one lamp is already off while the other is still on.
LED dimmer not working: solutions
Lamp flickers
Usually the lamp isn’t dimmable, the total power is below the dimmer’s minimum, or the dimmer isn’t made for LED. Try a universal LED dimmer or add a lamp.
Lamp buzzes or hums
This is often down to the combination of dimmer and driver. A different dimmer or a different lamp usually solves it.
Lamp keeps glowing or doesn’t switch off completely
A dimmer with leakage current or a switch with an indicator light can produce a faint glow. Read more in Troubleshooting LED lighting.
The dimming range is small
Some lamps only dim to 20 or 30 percent, or cut out at low light. That is down to the lamp. Check the product page and, if necessary, adjust the dimmer’s minimum brightness.
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Frequently asked questions
Which dimmer do I need for LED?
Can I dim an ordinary LED lamp?
Why does my dimmable LED lamp flicker?
Is trailing-edge dimming better than leading-edge dimming?
How do I dim an LED strip?
Kind regards,
Bas / LEDPLANET.NL