A 9W germicidal lamp in a modern compact fluorescent lamp form factor

Close-up of the electrodes and the safety warning

An EPROM. The small quartz window admits UV light during erasure.

A germicidal lamp is a special type of lamp which produces ultraviolet light (UVC). This short-wave ultraviolet light ionizes oxygen to produce ozone and can kill many surface pathogens (hence the name). Image File history File links Download high-resolution version (1517x348, 45 KB) A 9W germicidal lamp in a modern compact-fluorescent form factor File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Germicidal lamp Ultraviolet Germicidal Irradiation ... Image File history File links Download high-resolution version (1517x348, 45 KB) A 9W germicidal lamp in a modern compact-fluorescent form factor File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Germicidal lamp Ultraviolet Germicidal Irradiation ... A spiral type compact fluorescent light bulb. ... Image File history File links Download high-resolution version (870x1134, 78 KB) Summary Close-up of the electrodes and warning text on a 9W germicidal lamp in a compact-fluorescent form factor. ... Image File history File links Download high-resolution version (870x1134, 78 KB) Summary Close-up of the electrodes and warning text on a 9W germicidal lamp in a compact-fluorescent form factor. ... Image File history File linksMetadata Download high resolution version (1275x665, 575 KB) Title : EEPROM : The first INTEL EPROM, the 1702 (1971). ... Image File history File linksMetadata Download high resolution version (1275x665, 575 KB) Title : EEPROM : The first INTEL EPROM, the 1702 (1971). ... EPROM. The small quartz window admits UV light during erasure. ... Ultraviolet (UV) light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than soft X-rays. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Atomic mass 15. ... For other uses, see Ozone (disambiguation). ... A pathogen or infectious agent is a biological agent that causes disease or illness to its host. ...

There are two common type available:

• Low pressure lamps
• Medium pressure lamps

Low pressure lamps

Low-pressure lamps are very similar to a fluorescent lamp, with a wavelength 253.7 nm. To meet Wikipedias quality standards, this article or section may require cleanup. ... The wavelength is the distance between repeating units of a wave pattern. ...

The most common form of germicidal lamp looks similar to an ordinary fluorescent lamp but the tube contains no fluorescent phosphor. In addition, rather than being made of ordinary borosilicate glass, the tube is made of fused quartz. These two changes combine to allow the 253.7 nm ultraviolet light produced by the mercury arc to pass out of the lamp unmodified (whereas, in common fluorescent lamps, it causes the phosphor to fluoresce, producing visible light). Germicidal lamps still produce a small amount of visible light due to other mercury radiation bands. A phosphor is a substance that can exhibit the phenomenon of fluorescence (glowing during absorption of radiation of another kind) or phosphorescence (sustained glowing without further stimulus). ... It has been suggested that Kimax be merged into this article or section. ... Fused quartz is a man-made material manufactured principally from sands. ... General Name, Symbol, Number mercury, Hg, 80 Chemical series transition metals Group, Period, Block 12, 6, d Appearance silvery white Atomic mass 200. ... Fluorescence induced by exposure to ultraviolet light in vials containing various sized cadmium selenide (CdSe) quantum dots. ... The visible spectrum (or sometimes optical spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. ...

An older design looks like an incandescent lamp but with the envelope containing a few droplets of mercury. In this design, the incandescent filament heats the mercury, producing a vapor which eventually allows an arc to be struck, short circuiting the incandescent filament. For alternate meanings see Short circuit (disambiguation) A short circuit (sometimes known as simply a short) is a fault whereby electricity moves through a circuit in an unintended path, usually due to a connection forming where none was expected. ...

Medium pressure lamps

Medium-pressure lamps are much more similar to HID lamps than fluorescent lamps. 15 kW Xenon short-arc lamp used in IMAX projectors High-intensity discharge (HID) lamps include these types of electrical lamps: mercury vapor, metal halide (also HQI), high-pressure sodium, low-pressure sodium and less common, xenon short-arc lamps. ...

These lamps radiate a broad-band UV-C radiation, rather than a single line. They are widely used in industrial water treatment, because they are very intense radiation sources. They are not as efficient as low-pressure lamps but low-pressure lamps are very hard to manufacture in high wattages (over one kW). Medium-pressure lamps produces very bright bluish white light. The watt (symbol: W) is the SI derived unit of power, equal to one joule per second. ...

Auxiliary equipment

As with all gas discharge lamps, all of the styles of germicidal lamps exhibit negative resistance and require the use of an external ballast to regulate the current flow through them. The older lamps that resembled an incandescent lamp were often operated in series with an ordinary 40 W incandescent "appliance" lamp; the incandescent lamp acted as the ballast for the germicidal lamp. In electrical circuits, static resistance is the ratio of the voltage across a circuit element to the current through it. ... A ballast is a device used to start a gas discharge lamp, and, once the lamp is started, to limit the flow of electric current. ...

Uses

Further information: Ultraviolet Germicidal Irradiation

Germicidal lamps are used to sterilize workspaces and tools used in biology laboratories and medical facilities. They are also used wherever ozone is desired, for example, in the sanitizing systems of hot tubs and aquariums. They are also used by geologists to provoke fluorescense in mineral samples, aiding in their identification. In this application, the light produced by the lamp is usually filtered to remove as much visible light as possible, leaving just the UV light. A low pressure mercury vapor discharge tube floods the inside of a hood with shortwave UV light when not in use, sterilizing microbiological contaminants from irradiated surfaces. ... For television series episodes entitled Hot Tub, see Hot Tub (Drawn Together episode) or The Hot Tub (Seinfeld episode). ... For other uses, see Aquarium (disambiguation). ... A geologist is a contributor to the science of geology, studying the physical structure and processes of the Earth and planets of the solar system (see planetary geology). ... Minerals are natural compounds formed through geological processes. ... Coloured and Neutral Density filters An optical filter is a device which selectively transmits light having certain properties (often, a particular range of wavelengths, that is, range of colours of light, or polarizations), while blocking the remainder. ...

The light produced by germicidal lamps is also used to erase EPROMs; the ultraviolet photons are sufficiently energetic to allow the electrons trapped on the transistors' floating gates to tunnel through the gate insulation, eventually removing the stored charge that represents binary ones and zeroes. EPROM. The small quartz window admits UV light during erasure. ... Large power N-channel field effect transistor The field-effect transistor (FET) is a transistor that relies on an electric field to control the shape and hence the conductivity of a channel in a semiconductor material. ... The floating gate transistor is a variant of transistor that is commonly used for non-volatile storage such as flash, EPROM and EEPROM memory. ...

Germicidal lamps are also used in waste water treatment in order to reduce organic content.

Safety concerns

Short-wave UV light is harmful to humans. In addition to causing sunburn and (over time) skin cancer, this light can produce extremely painful inflammation of the cornea of the eye, which may lead to temporary or permanent vision impairment. For this reason, the light produced by a germicidal lamp must be carefully shielded against both direct viewing and reflections and dispersed light that might be viewed. Skin cancer is a malignant growth on the skin, which can have many causes, including repeated severe sunburn or long-term exposure to the sun. ... The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber, providing most of an eyes optical power [1]. Together with the lens, the cornea refracts light and, as a result, helps the eye to focus. ... Visual impairment is the functional loss of vision. ...