Everything you need to know about CCT or dual-white flexible strips

LED flexible strips have been around for many years now, successfully featured in hundreds and thousands of different applications. They’re long-lasting, flexible and small, and they are available in a range of colours and white temperatures to suit your different needs. Looking for bulkhead lighting for a hotel? 3000K is your temperature of choice. Looking for general lighting? 4000K will do the job. Lighting the work surfaces in a kitchen? A nice cool 6000K will light those surfaces so that you don’t cut your finger. White LEDs are available in a wide range of colour temperatures – the “normal” range being from around 2300K up to 9000K although warmer and cooler tones are available.

But what do you do when you need to change the mood of a room with lighting, say from 4000K during the lunch period to a romantic 2700K in the evening? A quality RGB strip could try and simulate these temperatures but it’s tricky, and the controllers often won’t get it spot on. Besides which, you’ll battle to get an RGB strip which can deliver a decently high CRI.

In cases like this, lighting designers and architects will want very specific temperatures – such as our 2700K and 4000K example and with a decent CRI, such as 80Ra and above. In the past such a requirement would result in two flexible strips being installed, one 2700K strip and one 4000K strip with each being controlled separately.

The LED lighting industry responded by creating what is now commonly called a CCT strip – a strip containing two different temperature chips, usually 3000K and 6000K but in truth these could be any two temperatures. The different whites could be mounted as a sequence of single colour chips – warm white / cool white / warm white / cool white – or as two epiwafers packaged into a single LED, also known as a 2-in-1 chip. Both chip configurations would operate in the same way: a strip with three copper tracks: a common anode, warm white negative and cool white negative. It’s essentially having two coloured strips on one FPC.

Whilst these strips are generally called CCT strips they can also rightfully be called dual-colour strips – since the colours need not be limited to white.

A single colour chip CCT strip
A 2-in-1 CCT strip

Whilst that solves the problem of having to install to different strips in a small location, the controlling of such strips could still be a challenge. LED controller manufacturers responded by creating colours for controlling the two white colours a little more seamlessly. CCT controllers – be they wall controllers or wireless remote controllers – will combine the dimming functionality of two white strips into one controller. By varying the brightness of each of the white chips, you can vary the overall emitted temperature of the strip. Different controllers vary in how they allow you to control the brightness of each of the white temperatures – the one Sunricher example below, has one “wheel” which will allow you to essentially set one temperature on a single brightness continuum from one temperature to the other.

A Sunricher CCT wall controller

 

CCT flexible strips are really uncomplicated – they are in essence two strips in one. The complexity as alwaysis in the controlling of these two strips to achieve the desired outcome, a problem which companies like Sunricher have solved.