Dimming – a brief guide

With the advent of LED lighting, it is now more important than ever to understand LED-dimming requirements, to ensure that the product is compatible with the system in place.

This guide is intended to give you a brief explanation of the terminology that is commonly used, so you can ensure the product selected is compatible with your current dimming system and is the best option available.

Incandescent and halogen lamps were dimmable as standard and could be used on all types of dimmers, with the exception being that the performance of the lamps was better on certain types of dimmers than with others. LEDs require additional components/drivers to allow dimming and certain drivers only have compatibility with certain dimming types.

Dimming – the technical bit

A dimmer is used to create the lighting ambiance but allows you to set the lighting levels to your individual requirements. A dimmer works by cutting the voltage, thus reducing the power to the lighting.

Dimming Types – a brief explanation

• Switched Mains – (non-dimming)This is an on/off function and seen most commonly – the product does not dim.
• Switch Dim – Here a switch controls the dimming of the lighting. When the switch is pressed and held, the lighting will dim down – press and hold again and the lighting will dim back up (get brighter) again.
• Leading Edge or Triac Dimmer – Both are common forms of dimming and are historically used with incandescent lamps or low voltage lamps, as they work well with transformers. These dimmers tend to have a high maximum load, to manage the dimming of the 50w 12v lamp commonly used in substantial numbers. However, this makes it harder to use such systems with LED products, due to the low load required, but this can usually be overcome in the majority of cases.
• Trailing Edge Dimming – Trailing edge dimmers are historically used with mains voltage halogen lamps and tend to have a lower load requirement, thus making it easier to dim LED products. Trailing edge dimmers often have a smooth, silent dimming function and do not have the common issue of noise interference (buzzing), commonly associated with leading-edge dimming.
• 1-10v Dimming – With this system dimming tends to be smoother and can dim to lower levels, however additional wiring is required, rather than simply being able to change the controlling switch.
• DALI Dimming – Digital Addressable Lighting InterfaceDALI dimming is a commonly used digital dimming system, which requires a DALI cable, running from a controller to each fitting, but also specific Dali compatible fittings to work. The system assigns an individual address to each fitting and will usually be integrated into a building’s management system. It is essential that specific DALI compatible products be used for this system to function correctly.
• DSI Dimming – Digital Series InterfaceDSI is another form of digital dimming, enabling the end user to ‘group’ fittings together and also use special controls; e.g. Daylight Harvesting. Again, specific wiring is required and the dimming is controlled via the use of a lighting ballast.
• DMX – Digital MultiplexDMX is commonly used for colour changing products. The DMX signal is produced via a lighting control system and requires dedicated cabling between the driver and controller. This is generally used with professionally designed lighting control systems, such as stage or performance lighting. Negotiating the correct replacement which is compatible with your dimming requirements can cause uncertainty for further support please contact us to enable the right solution is found.