Light-emitting wire
ElectroLuminescent Wire consists of a concentric series of layers, each performing a different function. In the center is a solid copper conductor, which is coated with an electroluminescent phosphor. Two very fine wires are wrapped around the phosphor. A clear or colored plastic sheath comes next, and a second plastic sheath surrounds the first. The functions of each of these layers are as follows:
The center copper conductor and the two fine wires together supply power. The copper conductor also provides a small amount of mechanical rigidity and is used as a substrate upon which to deposit the phosphor. The phosphor is the key element of EL wire; it emits light when subjected to an AC field. The inner plastic sheath protects the phosphor and in some cases is used to filter the light produced by the phosphor, emphasizing certain colors. The outer plastic sheath provides further protection. Many phosphors are highly sensitive to moisture; the two sheaths together provide good protection against infiltration.
EL wire can be driven by any AC source. Power is applied between the inner conductor and the two outer wires (which are tied together). This applies an AC field across the phosphor, causing it to glow. A high voltage in the range of 100V is required to make the wire glow brightly. It can be produced from an inverter, from the mains (e.g. a wall outlet), from an audio amplifier, from a signal generator, etc. If the voltage is not high enough (as in the case of a medium power audio amplifier), it can be stepped up with a transformer. When the wire is connected to a high current source like the AC mains, a fuse and/or current limiting resistor is used for safety due to the danger of a short circuit.
EL wire acts as a capacitor, with capacitance proportional to the length of the wire segment. This means that given a constant voltage, power consumption is proportional to frequency. Light output is also roughly proportional to frequency. See the appropriate table for a more accurate guide to the relationship of light output to frequency and voltage.
The spectrum produced by some types of EL wire varies with the frequency of the applied power. Those that are filtered (have a colored inner sheath) vary less in color. The “aqua” (“ice blue”) wire is most sensitive; its color can be varied from deep green to deep blue by varying the power frequency from 60 Hz to 6 kHz. Due to its capacitive nature, to maintain constant brightness as frequency is swept the voltage must also be varied, from high voltage at low frequency to a lower voltage at high frequency.
Source: Shawn Van Every and Matt Pilotti, Walking Productions.
Contact: Torche, Gerlach, NV, USA.
