Typical<unk>  with F71T12 markings. This example is a 71-inch, bi-pin, 100 watt model, the most common. Inside a preheat, bi-pin<unk>  A high-pressure<unk>  under power<unk> s (sometimes called<unk>  bulbs in the United States or<unk>  tubes in Europe) are the part of a<unk>  bed, booth or other<unk>  device which produces ultraviolet light responsible for indoor<unk> . There are hundreds of different kinds of<unk> s most of which can be classified in two basic groups: low pressure and high pressure. Within the industry, it is common to call high-pressure units "bulbs" and low-pressure units "lamps", although there are many exceptions and not everyone follows this example. This is likely due to the size of the unit, rather than the type. Both types require an oxygen free environment inside the<unk> . Fluorescent<unk> s require an electrical ballast to limit the amount of current going through the<unk> . While the resistance of an incandescent<unk>  filament inherently limits the current inside the<unk> ,<unk> s do not and instead have negative resistance. They are plasma devices, like a neon sign, and will pass as much current as the external circuit will provide, even to the point of self-destruction. Thus a ballast is needed to regulate the current through them.<unk> s are installed in a<unk>  bed,<unk>  booth,<unk>  canopy or free standing single bulb<unk>  unit. The quality of the tan (or how similar it is to a tan from the natural sun) depends upon the spectrum of the light that is generated from the<unk> s.
Tanning lamp
Slit lamp
Eye chart
Dolorimeter
Snellen chart
X-ray vision
Laser microtome
Solar viewer