Comment fonctionne une LED, concrètement ?

Une LED émet de la lumière lorsqu'un courant la traverse à la jonction de deux semi-conducteurs. Le composant chauffe très peu, consomme une petite part de l'énergie d'une halogène et se pilote au volt près. Ce que vous choisissez en boutique, c'est le résultat de cette mécanique.

Comment fonctionne une LED dimmable ?

La variation d'intensité réduit le courant qui alimente la diode, en impulsions très rapides ou en abaissant la tension. L'œil perçoit une baisse de luminosité. Une condition ne se négocie pas : l'ampoule et le variateur doivent être compatibles, sinon la lumière saute ou grésille.

Comment fonctionne une lampe LED sans fil ?

Une batterie lithium alimente la même diode, par l'intermédiaire d'un petit driver. Sans câble, plus de contrainte de prise : la lampe se pose là où la lumière manque, et se déplace au fil des saisons.

Quelle LED pour quelle pièce ?

Partez de l'usage : lire, cuisiner, se détendre. Le séjour demande une lumière modulable autour de 2700 K, la chambre une lumière chaude et basse, la cuisine un éclairage dirigé sur les plans de travail, la salle de bain un modèle protégé de l'humidité.

Pourquoi les ampoules LED restent-elles allumées ?

Une LED s'éclaire avec très peu de courant. Un interrupteur à voyant, un câblage capacitif ou un variateur laissent passer quelques milliampères : assez pour produire une lueur visible la nuit, sans que l'interrupteur soit en position marche.

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How an LED works: choosing the right light for each room

This article is also available in French: Comment fonctionne une led

26/09/2026 · 8 min read · By the Designix team

Start with the colour temperature, then the base. An LED produces light when a current passes through the junction of two semiconductors: it gives off little heat, lasts a long time and can be controlled. For a living room, aim for 2700 K to 3000 K with an E27 base; in a bathroom, the ingress protection rating comes first.

How does an LED work, in practice?

An LED emits light when a current passes through it at the junction of two semiconductors. The component heats up very little, uses a small fraction of the energy of a halogen and can be controlled to the volt. What you choose in store is the result of that mechanism.

For a complete fitting, starting from a base designed for the diode avoids compatibility surprises: our selection of LED lighting brings together models whose light source is built in from the start.

How does an LED bulb work?

Inside the bulb, a driver converts the 230 V mains supply into a low-voltage direct current. It is what determines the stability of the light and the lifespan. On a fitting with integrated LED, everything is replaced as one unit; on a model with a base, only the bulb is replaced.

Base	Where it is used	What it means
E27	Ceiling lights, pendants, floor lamps	Interchangeable bulb, very wide choice
E14	Small lamps, wall lights, chandeliers	Reduced format, more modest wattages
GU10	Adjustable spotlights, kitchen	Directional beam, 230 V supply
Integrated LED	Slim fittings, strips, battens	No replacement possible

In a survey of 249 listings in our catalogue as of 30 September 2026, 23% have an E27 base and 20% an integrated LED. The base is not a detail: it decides what you will be able to change in five years. Our guide to types of LED bulbs details each format.

Efficiency: more light per watt consumed
Heat: little given off, without rising in temperature
Control: adjustable brightness and hue on compatible models

How does an RGB LED work?

Three chips (red, green, blue) or a multi-die chip are mixed to produce colour, including white. Control is via a remote or an app. These lamps are for atmosphere rather than reading.

Which LED for which room: the decision table

	Room	Colour temperature	Common base	Ingress protection
Living room	2700–3000 K, warm white	E27 or integrated LED	IP20	Useful: from dinner to evening
Bedroom	2200–2700 K, very warm	E14 or integrated LED	IP20	Useful: dim before bedtime
Kitchen	3000–4000 K, neutral white	GU10 for spotlights, E27 for pendants	IP20 on the ceiling	Little use outside accent lighting
Bathroom	3000–4000 K, neutral white	Integrated LED or protected E27	IP44 minimum, IP65 near the shower	Useful on a mirror
Hallway and stairs	2700–3000 K, warm white	E27 or integrated LED	IP20	Useful as a night light
Terrace and outdoors	2700–3000 K, warm white	E27 on a weatherproof wall light	IP65	Little use, prefer a sensor

If you would rather confirm your colour temperatures and bases before ordering, the Designix team replies directly via the contact page.

How does a dimmable LED work?

Dimming reduces the current feeding the diode, in very rapid pulses or by lowering the voltage. The eye perceives a drop in brightness. One condition is non-negotiable: the bulb and the dimmer must be compatible, otherwise the light flickers or buzzes.

In a survey of 249 listings as of 30 September 2026, dimming is stated as compatible on 26% of the completed listings. Our article on dimmable LED details the cases where the dimmer voids the warranty of the fitting.

Why won't my LED lamp turn on?

Incompatible dimmer: designed for halogen, it does not go low enough
Base not screwed in properly or an oxidised socket: the contact is intermittent
Driver out of order: on an integrated source, the whole fitting is replaced
Upstream circuit: check the switch and the circuit breaker before blaming the bulb

Why does an LED flicker on a dimmer?

The minimum load of the dimmer is almost never reached by an LED bulb. Too little current flows, the dimmer regulates poorly and the light pulses. A model marked as dimmer-compatible, or a compensation load, solves the problem.

How does a cordless LED lamp work?

A lithium battery powers the same diode through a small driver. Without a cable, there is no socket constraint: the lamp goes where light is missing, and moves with the seasons.

How is an LED lamp recharged?

USB-C: your phone cable will do
Induction base: the lamp is set down and charging starts on its own
Removable battery: rare, but practical on bedside models

What battery life can you expect from a cordless lamp?

Battery life depends on the brightness chosen, not on a single figure. Pushed to maximum, the battery drains quickly; as accent lighting, a model with adjustable brightness easily lasts the evening. A cordless bedside lamp is therefore chosen as much for its adjustment range as for its capacity.

Which LED for which room?

Start from the use: reading, cooking, relaxing. The living room needs adjustable light around 2700 K, the bedroom a warm, low light, the kitchen directional lighting on the worktops, the bathroom a model protected from humidity.

Which base for a living space?

E27 remains the safe choice for a living room: the bulb can be changed, and so can the hue. An LED ceiling light suits low ceilings, where the light must come down without taking up space. Above a table, a dining room chandelier structures the room and hangs at eye level.

Which colour temperature for a bedroom?

The bedroom copes poorly with cool white: it delays falling asleep. Stay between 2200 K and 2700 K, with low brightness at the end of the day. Our comparison of white or yellow light helps you decide, and calculating how many lumens for a bedroom avoids buying too powerful. A bedroom light with adjustable brightness settles both at once.

Why does the ingress protection rating change everything in a bathroom?

IP measures resistance to dust and water. The closer you get to a water point, the higher the rating must be: it decides whether the fixture lasts over time. In the survey of 249 listings, IP20 accounts for 80% of the completed listings, while IP44 and IP65 remain in the minority.

IP20: dry rooms, never within reach of splashes
IP44: area near the sink, occasional splashes
IP65: immediate vicinity of the shower or bath

The Decoration by Room collection had 24,014 references as of 30 September 2026, including a large bathroom section. For a living room to be completely rethought, our living room renovation offer starts with the lighting plan before the furniture. In the kitchen, kitchen lighting is added alongside the ceiling light, never in its place.

One last reference point if you are still hesitating between two models: the Designix Google listing remains available, with up-to-date buyer reviews.

Designer LED lighting for every room

See the whole selection: Lighting

Which room do you want to change the light in first?

Why do LED bulbs stay lit?

An LED lights up with very little current. A switch with an indicator light, capacitive wiring or a dimmer let a few milliamps through: enough to produce a visible glow at night, without the switch being in the on position.

Where does the residual glow of an illuminated switch come from?

The indicator light in the switch draws a small current that passes through the lamp to return to the consumer unit. The more frugal the bulb, the more that current is enough to light it. A more power-hungry bulb would mask the phenomenon without removing it.

How do you switch off an LED that stays lit?

Switch without an indicator light: the most straightforward solution
Discharge resistor: fitted by the electrician, it absorbs the residual current
Bulb of another reference: some tolerate low current better
Dedicated dimmer: it actually cuts the circuit at the zero position

These last three cases mainly concern older installations. Our feature on switching to all-LED lighting explains what to check before replacing a whole set of bulbs.

Your questions about LED

How do you check whether an LED works?

Test it in a socket you know is powered, then compare with a bulb you know works. If it stays off elsewhere, the LED is at fault; if it lights up elsewhere, look at the fitting, the switch or the dimmer.

What are the drawbacks of LED lamps?

An LED is sensitive to heat: poorly ventilated, it loses lifespan. It can also flicker with an incompatible dimmer, and some produce light that is too cool for a bedroom.

What should you do when the LEDs no longer light up?

First check the power supply (circuit breaker, switch, transformer or driver), then test the bulb in another socket. On an LED strip, look for the break at the cut marks.

Can an LED burn out?

Yes. It is not a filament that breaks, but the internal electronics that wear out, often because of heat or unsuitable voltage. An LED that blackens in the centre is at the end of its life.

How does a string of LED lights work?

Each light point is a small LED powered by a low-voltage circuit, most often via a transformer or batteries. The built-in electronic module decides whether the string stays steady, blinks or is controlled remotely.