The short answer
TRIAC or phase-cut controls a compatible driver by changing the AC mains waveform. A 0–10V system sends an analogue signal to a compatible control input. DALI uses digital commands to compatible devices, including individually addressable groups. None of these inputs is automatically interchangeable; confirm the exact models and wiring diagrams before purchase.
TRIAC and phase-cut: mains-side control
A phase-cut wall dimmer alters part of the incoming AC waveform. The connected driver must explicitly support that kind of mains dimming. Products may specify leading-edge, trailing-edge or both; “TRIAC” is often used in sales copy for phase-cut, but is not a complete compatibility specification.
Phase-cut can suit an existing dimmer position in a small installation. However, a mismatch between dimmer and driver can cause flicker, buzzing, a narrow dimming range, failure to turn off or erratic behaviour at low levels. Check minimum load and the manufacturer’s compatibility list where available. Mains-side changes must be carried out by a competent person.
0–10V: a separate analogue control signal
A 0–10V-capable driver receives normal power plus a separate low-voltage control signal. Its light output responds to the control voltage according to its specification. The control signal is not the supply for a 12V strip, and it does not replace the driver’s mains input.
Check whether the driver expects an active source or a sinking controller, how it behaves at the bottom of its dimming range, whether an additional switched supply is needed for full off, and the allowed number of drivers on the controller. Products marketed as “1–10V” may behave differently at the low end.
DALI: digital control and addressed zones
DALI is a lighting-control protocol based on IEC 62386. A DALI system sends digital commands to compatible control gear. Individual devices, groups or all devices can be addressed, and a system can recall programmed scenes. DALI is useful when a commercial installation needs flexible zoning and later reconfiguration.
A DALI-compatible driver alone is not a complete system: a compatible control device, bus supply and commissioning plan may be required. Verify whether a product supports DALI, DALI-2 or a particular DALI device type according to the system design.
Which method fits the project?
The best choice depends on the existing controls and how much independent control the project needs.
| Method | Signal path | Useful when | Important check |
|---|---|---|---|
| Phase-cut | Modified AC power to compatible driver | A suitable mains dimmer is already planned | Leading/trailing edge and load compatibility |
| 0–10V | Separate analogue control pair | Simple dimming of compatible drivers | Controller interface and low-end/off behaviour |
| DALI | Digital lighting-control bus | Addressed zones and scenes | DALI components and commissioning |
Where does PWM strip dimming fit?
Many 12V and 24V constant-voltage LED strips can be dimmed with a suitable PWM controller on the low-voltage side of a compatible CV power supply. In that arrangement, the supply might be non-dimmable; the downstream controller changes the strip output. Its voltage and current limits must cover the connected strips.
A 0–10V input, DALI input or phase-cut AC input does not appear on every supply. Do not connect a wall dimmer upstream of a non-phase-cut supply and assume a PWM controller will make the system compatible.
Five questions to settle before ordering
Write down the answers before choosing a dimmer.
- Is the LED load CV or CC, and what voltage/current does it require?
- Does the exact driver support phase-cut, 0–10V, DALI, a combination, or none?
- Where does control take place: mains input, driver control terminals or low-voltage output?
- What are the minimum/maximum load, dimming range and full-off behaviour?
- Are all controller, driver, cable and installation requirements documented?
Frequently asked questions
Can I use a standard household dimmer with any LED driver?
No. The driver must be specifically compatible with the dimmer’s phase-cut method and load range.
Is 0–10V the same as a 10V power supply?
No. 0–10V is a control signal for a compatible driver, not the LED load supply.
Can DALI dim a 24V LED strip?
Yes, with a suitable DALI-compatible constant-voltage driver or a compatible DALI controller and correctly rated strip supply, depending on the system design.
Technical references
Use the current datasheet for the exact product you install. These manufacturer and standards resources explain the general principles.
Planning a professional LED installation?
Browse Glowfy power supplies, or send our Birmingham team the load specification and installation details for product guidance.