LED Dimming Explained: The Right Way to Dim LED Luminaires
Last updated: 24 August 2026
Connect an old dimmer onto a new LED downlight and you'll often get a light show nobody asked for; buzzing, flicker, a fitting that won't drop below 50%, or one that drops out entirely near the bottom of the dial. The fitting usually isn't faulty. The dimming method is wrong for the driver.
LEDs don't dim the way incandescent lamps did. An incandescent filament was a simple resistive load, chop the mains voltage with a cheap dimmer and the lamp got dimmer. An LED luminaire is an electronic system in which a driver converts mains power into a tightly controlled current, and that current is what you need to vary. Match the control method to the driver and you get smooth, deep, flicker-free dimming. Get it wrong and you get callbacks.
Why this matters
For a contractor, a dimming mismatch is margin gone, a return visit, a swapped dimmer, an argument about who pays. For a building owner or facilities manager, it is flicker that triggers headaches in an open-plan office, a boardroom scene that looks cheap, or a warehouse where the lights strobe against moving machinery. It's an important issue about whether the lighting performs smoothly and reliably in the space.
The five ways to dim an LED - and where each belongs
Phase-cut (Triac/leading and trailing-edge dimmers): These are the old wall dimmers built for incandescent loads. They work by varying the amount of current that flows through to the driver. Some LED drivers are designed to tolerate them, but compatibility is hit-and-miss: the dimmer and driver have to be matched pair-by-pair, and even then, you often can't dim below 10–20% without flicker or dropout. Fine for a small residential-style retrofit on a known compatible combination; a poor choice for any serious commercial job.
0–10V (and 1–10V) analogue: The driver reads a low-voltage DC control signal — 0 (or 1) volt is dim, 10 volts is full. Simple, cheap, and reliable for basic jobs. It limited to a single broadcast channel, so every fitting on the line dims together as one group; there's no feedback from the fitting; and over long cable runs the control voltage can sag, so distant fittings sit at a slightly different level. Good for a single open-plan zone or a daylight-linked perimeter row. Not the tool for individually addressable control.
PWM (pulse-width modulation): Instead of lowering the current, PWM switches the LED fully on and off very fast and varies the ratio of on-time to off-time. Done at a high enough frequency, it's invisible and dims very deep. Done too slowly it's a flicker generator. PWM is common inside fittings and in some colour-mixing gear, but the switching frequency is the thing to interrogate.
DALI / DALI-2 (Digital Addressable Lighting Interface): A two-wire digital bus that sends each fitting its own digital command. Every luminaire has an address, so you can dim one fitting, a group, or a whole floor independently, set scenes, and because the bus is bidirectional, read faults and energy data back. DALI-2 (IEC 62386) tightened certification so gear from different vendors actually interoperates, and added proper support for sensors and switches, not just drivers. For commercial fit-outs where the project budget supports it, DALI-2 is usually the most robust and flexible option.
Wireless (radio mesh — Bluetooth Low Energy, Zigbee, Wirepas): Same idea as DALI, but the command travels wirelessly instead of through a separate control cable. Each fitting can receive its own instruction, and fittings pass messages between each other so the system can cover a larger area and keep working if one pathway is weak. The common practical options are Bluetooth Low Energy (BLE) mesh, Zigbee and Wirepas-based mesh systems. DALI+ over Thread is also emerging as a standards-based DALI-over-wireless/IP pathway, but it should be treated separately from general-purpose wireless mesh options. The main benefit is that no extra control cabling is needed, which makes wireless attractive for retrofits, heritage buildings and sites where running new cables is difficult. The trade-off is that wireless systems share radio space with other technologies, such as Wi-Fi, so they need a basic radio plan. They also need ongoing software, firmware and security management, which a simple wired control system usually does not require. Emergency lighting on a wireless system is still governed by AS/NZS 2293.
The detail that ruins good fittings - the dimming curve
Even with premium DALI luminaires, people report "jumpy" dimming or visible steps at low light. The usual culprit is the dimming curve, which is the relationship between the control signal and the actual light output.
The human eye perceives brightness logarithmically (the Weber–Fechner law). In a dark room a small increase in light output is obvious; in a bright room the same increase is barely noticeable. A logarithmic curve packs most of its fine control steps into the bottom of the range. Approximately the lowest 20% of output gets about three-quarters of the available steps, so manual dimming feels smooth and natural. A linear curve maps signal to output 1:1, which feels jumpy by hand but is exactly what a daylight sensor or building-management closed loop requires. DALI-2 mandates the logarithmic curve as the default, but drivers can be configured either way and picking the wrong one is behind a lot of "bad dimming" complaints.
Why flicker-free performance matters
The biggest shift in dimming over the last few years is not a new protocol but a stronger focus on light quality. Flicker used to be dismissed as a vague complaint; now it is widely recognised as a real performance issue that affects comfort, visual stability and the way a space feels in use.
In simple terms, flicker rules and guidance are moving the industry toward a higher standard of light quality. The aim is to make sure LED lighting stays visually stable, not only at full brightness but also when it is dimmed. This matters because some flicker is obvious, while other forms are harder to see directly but can still make moving objects appear to stutter or look unstable. The practical implication is that a product should not be accepted as suitable just because it is labelled “dimmable”. The luminaire, driver and control system need to be checked together to make sure the light remains stable and comfortable across the dimming range required for the project.
What to do about it on Monday
Stop treating "dimmable" as a yes/no box on the data sheet. Before you specify or quote, settle four things together: the driver, the control protocol (wired or wireless), the dimming curve, and the minimum dim level you actually need. Match them as a system. A premium DALI-2 driver, or a quality wireless system, will dim flicker-free to 1%, or even 0.1%, but only if it is commissioned with the right curve and a control method it was built for. The fitting is rarely the problem; the pairing is.
Dimming-method selection reference sheet
Match the protocol to the application before the order goes in.
Method | How it controls | Dims to (typical) | Individual addressing | Feedback / diagnostics | Best for | Avoid for |
Phase-cut (TRIAC) | Chops mains waveform | ~10–20% | No | No | Small retrofits on verified-compatible pairs | Any scaled commercial job |
0–10V / 1–10V | Analogue DC signal | ~1–10% | No (group only) | No | A single zone, daylight perimeter row | Multi-zone, scene-based control |
PWM | High-speed on/off ratio | Very low (driver-dependent) | Within fitting | No | Colour mixing, in-fitting control | Anywhere the switching frequency is unknown / low |
DALI-2 (wired) | Digital addressed command | 1% — best 0.1% | Yes (per fitting) | Yes (faults, energy) | Commercial fit-outs of any scale | Tiny single-fitting jobs where it's overkill |
Wireless mesh (BLE / Zigbee / Wirepas) | Radio-mesh addressed command | 1% — best 0.1% (driver-led) | Yes (per node) | Yes (faults, energy) | Retrofit and hard-to-cable sites | Dense RF environments without a channel plan |
Pre-spec compatibility checklist
Run this before the order goes in:
Driver dimming type — does the driver explicitly support your chosen control method (phase-cut / 0–10V / DALI-2 / wireless)? "Dimmable" alone is not an answer.
Minimum dim level — stated as a percentage, and stated as flicker-free to that level — not just “off”.
Flicker performance — ask for written confirmation that the driver remains flicker-free at full output and throughout the operating dimming range you require.
Dimming curve — confirm logarithmic vs linear is selectable, and decide which the space needs.
Mixed vendors — if you're combining drivers, sensors and controllers from different brands, insist on DALI-2 certification (not just "DALI compatible") so they interoperate.
Cable runs (0–10V) — for long runs, check voltage drop on the control line won't leave distant fittings sitting dimmer than the rest.
Bus limits (DALI) — keep within the line's device count and length budget (a DALI line tops out around 300 m with a maximum 2 V bus drop), and plan the power supply per line.
Wireless coexistence — for radio-mesh systems such as BLE mesh, Zigbee or Wirepas, plan the RF environment against site Wi-Fi and other wireless services, confirm node count and mesh depth meet the latency you need, and agree the firmware-update and security lifecycle. Treat DALI+ over Thread separately where the design objective is standards-based DALI over wireless or IP. Wireless emergency luminaires must still meet AS/NZS 2293.
Group vs scene plan — map zones and scenes before commissioning, not after.
DALI commissioning sequence (get the curve right first time)
Address every driver on the line and confirm each responds individually.
Assign fittings to groups and build the scene plan.
Set the dimming curve per zone — logarithmic for hand-dimmed spaces (retail, boardrooms, hospitality), linear for sensor/BMS-driven spaces (warehouse daylight harvesting, car parks).
Set fade times for scene transitions.
Test the bottom of the range — dim to the specified minimum and confirm no flicker, no dropout, and smooth steps.
Verify sensor and switch behaviour (occupancy off-delay, daylight setpoints). On a wireless mesh, confirm every node joins and check signal/hop health across the floor.
How enLighten can help
As an Australian designer, manufacturer and supplier of commercial LED luminaires and lighting controls, with more than 17 years in the market, enLighten supplies the luminaire and its control as a single matched system, so the dimming behaves on day one rather than being assembled from mismatched parts and hoped into working.
That covers both wired DALI-2 and wireless mesh control. Where running a control wire is impractical i.e. retrofits, occupied buildings, heritage fabric, awkward outdoor and public-realm sites, enLighten can consider practical wireless options such as Bluetooth Low Energy mesh, Zigbee and Wirepas-based systems, selected to suit the building layout.
If you are scoping an office, warehouse, car park or public-realm project and want the dimming resolved as part of the lighting system, involve enLighten at the specification stage, before fittings are ordered and installed.
FAQs about emergency lighting compliance in Australia
Why does my LED flicker when I dim it?
What's the best way to dim commercial LED lighting?
What's the difference between 0–10V and DALI dimming?
Can you dim LED lights wirelessly?
Can I use my old dimmer switch on LED lights?
What is a dimming curve and why does it matter?
How low can LED lights dim?
A good-quality driver can reach 1%, and the best dim to 0.1%, without flicker. Cheaper drivers stop around 10% or flicker below it. The minimum dim level should be specified as part of a project.
Need help selecting the right dimming solution?
Talk to the enLighten team about DALI-2, wireless controls, flicker-free performance and LED luminaires designed for smooth, reliable dimming from day one.