Definitions and Glossary
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Neon / cold cathode tubes, fluorescent lamps and HOTFIL tubes

Neon / cold cathode tubes are the term for colored, individually manufactured luminous tube for advertising (neon) or lighting (cold cathode) purpose.  

Fluorescent lamp specifies normally an industrially manufactured, straight, round or hairpin shaped luminous tube with fixed dimensions and fixed electrical data for lighting purpose indoors and outdoors. 

Luminous tubes is the common term for Neon/cold cathode and fluorescent lamps; they are based on the same physical principle:

A closed glass tube, filled with inert gas(es) or vapors under low pressure, carrying electrodes on both ends. High voltage applied to these electrodes force electrons out of the electrodes and through the gas, which emits light by electricity passing through (thus also called gas discharge lamp). Gas fill and often fluorescent material converting parts of the light into visible range determine the color of light emitted.   

Hot cathode is the term for the electrode in gas discharge lamps often in shape of a multiple coiled wire, similarly as known in incandescent lamps. The electrode wire (mostly made from tungsten) is glowing in lamp operation, therefore the term "hot cathode". Hot cathode electrodes for gas discharge lamps are coated on the surface with a material facilitating electron liberation; this coating requires the high temperature for proper operation. This electrode type is employed mainly in fluorescent lamps today. 

Cold Cathode is the term for large diameter neon tubing for lighting purpose as well as for the electrode principle used in Neon sign tubes and cold cathode illumination tubes (definition as used in this website). The electrode metal is often cup shaped and can be had with or without coating for facilitating electron liberation. This type of electrode is easier in handling during lamp processing and permits a long lamp life. Disadvantage is the necessity of high voltage (more than 500 volts, often more than 1000 volts) for lamp start and operation. Main use of this electrode is sign tubing and hard-to-reach architectural accent lighting. 

Note: The "Cold Cathode" has higher losses in lamp operation and thus runs hotter on the outside than a "hot cathode"!

HOTFIL-tubes are individually shaped and colored, handcrafted luminous tubes equipped with hot cathode (hot filament) electrodes.
The name is derived from "
HOT FILAMENT" describing the electrode type. 

Conditioning describes in the present terminology the process of conversion of an atmospherically stable electrode coating substance (also called "activation mass" into the working form, which is stable only under vacuum. This conversion must take place at high temperatures at reduced pressure. The reaction waste products are evacuated after the conditioning process is completed out of the tube together with other impurities; then the "clean" tube is filled with the operating gas.



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