What is Dimming?

What is a dimmable led? from Fern Howard Ltd

Dimmable LED luminaires save energy and create comfortable light levels for different activities and areas. Two different types of dimming control are available, analogue and digital.

Types of dimming

Analogue Dimming

The main method of analogue dimming is 1-10 Volt, a low current system that is easy to install. The dimmer produces a 1-10V DC voltage supply that can be increased or decreased smoothly, normally by using a rotary or slide dimmer.

Dimming requires a separate control cable to be run to each fitting on the circuit. This ‘notifies’ the driver when the power to the LEDs should be changed. As this is a direct current system, correct polarity must be maintained for the system to work.

This type of dimming is available with Fern Howard luminaires. A 1-10V dimmer switch is required(not supplied by Fern Howard).

Digital Dimming

Digital dimming sends a digital signal along a pair of control cables; it does not suffer from mains cable interference.

In a non-addressable system the control cables run directly between the switch (reactive or push-to-make) and the luminaires. All luminaires connected to that switch will be controlled as a group.

In an addressable system, each luminaire is assigned a unique digital address and can be controlled individually.

Digital control systems are most easily split by signal
• SwitchDIM / TouchDim
• DALI (Digital Addressable Lighting Interface)

Digital dimming systems

Switch/Touch Dim

Switch / Touch Dim

The most popular and simplest option for digital dimming, this operates through a push or reactive switch wired to each luminaire in the circuit via a 4-core cable. The switch controls both dimming and power on and off.

Pushing the button sends a pulse to the ballast. This reads the pulse and controls the lamp accordingly. All luminaires in the circuit are controlled together.

This type of dimming is available with Fern-Howard luminaires and requires a reactive push switch(not supplied by Fern Howard)

DALI (Digitally Addressable Lighting Interface)


This standard is employed by all manufacturers offering DALI ballasts.

By assigning a unique address to each luminaire in a circuit, they can be individually controlled or formed into groups. Pre-set ‘scenes’ can also be created for different activities or for different times of day. Controlled via a wall interface panel, or by a PC in a central location,

DALI is compatible with daylight sensors and PIR.

DALI is available with Fern-Howard luminaires.