Low Pressure Mercury Vapour Lamp Diagram

A sodium vapor lamp is a gas discharge lamp that uses sodium in an excited state to produce light at a characteristic wavelength near 589 nm.

Low pressure mercury vapour lamp diagram.

This coating covers more than 70 of the diameter of the lighted length of the lamp. The first mercury vapor lamps were in a lower pressure tube. In low pressure mercury vapor lamps only the lines at 184 nm and 254 nm are present. Again transition of the electrons requires least amount of input energy from a colliding electron.

The aperture phosphor coated lamps that jelight company produces employ the same basic design as the double bore low pressure mercury vapor lamps with the exception of a special phosphor coating. As pressure increases the chance of multiple collisions gets increased. Fused silica is used in the manufacturing to keep the 184 nm light from being absorbed. Amalgam lamps use a mercury amalgam mix to control mercury vapor pressure.

Two varieties of such lamps exist. In case of fluorescent lamp the mercury vapour pressure is maintained at lower level such that 60 of the total input energy gets converted into 253 7 nm single line. One would tip the lamp and electrical contacts on each side of the lamp would send electricity through a liquid mercury which started the lamp. Low pressure and high pressure low pressure sodium lamps are highly efficient electrical light sources but their yellow light restricts applications to outdoor lighting such as street lamps where they are widely used.