Explaining Electroluminescent Wire – How It Works and What It Is Used For
Posted: Nov 28, 2012
Electroluminescent wire, which name is normally abbreviated to EL wire for ease of writing and reading, is a strand of copper wire coated in phosphor. The phosphor is excited to the point of luminescence using an alternating current. The resulting glowing wire is used in all sorts of applications, from Christmas lights to decoration of structures and vehicles; and from emergency lighting installations to clothes or toys.
The light given off by electroluminescent wire is called “cool illumination” – a reference not to the fact that it looks awesome but to its power of giving out light without giving off any heat. Heat in a lighting situation is not really desirable, except where the specific purpose of the installation is to work as a heat lamp – so the wire scores over many other sources of light at this point.
The lack of heat is thanks to a lack of resistance in electroluminescent wire – which is so efficient in converting energy to light that it generates no warmth (as noted), lasts for hours on a single small power source, and may be used in enormous lengths with no loss of signal or power fidelity.
The wire is made up of five basic elements, three of which have a direct impact on the generation of the light. The first element is the copper core – a relatively thick wire, which is coated with phosphor. The phosphor covered wire at the core is then wrapped around by a much thinner coil of copper wire.
These three elements are charged and discharged to make the phosphor emit light. The alternating current is normally within the range of between 90 and 120 volts, at a rating of roughly 1, 000 Hz. The current is applied between the two wires (the phosphor coated core wire, and the thinly coiled wire surrounding it). The two wires between them form a coaxial capacitor, which excites the phosphor enough that it begins to emit light.
The other two components of electroluminescent wire are the plastic sheaths that surround everything else. Normally the wire is first sheathed in clear plastic, for protection (to keep the wire elements away from touch or other intrusion). The second sheath may be dyed any one of a number of colours, normally organic, which combine with the bluish glow emitted by the phosphor to create the colour desired. As a result, the colours in which electroluminescent wire may be found are limited by the colours that can be produced by combining other dyes with the blue and green elements of the phosphor glow.
Normally, the current in the wire is created using a resonant oscillator, which is necessary to develop the high drive signal required. The capacitance rating of the wire means that when a coiled transformer (inductive) is introduced into the mix the whole thing becomes, in effect, a tuned oscillator (LC), which explains the efficiency of the whole setup.