Lamps of today are high pressure lamps with a fused quartz inner discharge tube.
High pressure mercury vapour lamp working principle.
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.
Two varieties of such lamps exist.
The light would intensify as the arc grew stronger in the tube.
Developed in the 1960s they are similar to mercury vapor lamps but contain additional metal halide compounds in the quartz arc tube.
A metal halide lamp is an electrical lamp that produces light by an electric arc through a gaseous mixture of vaporized mercury and metal halides compounds of metals with bromine or iodine it is a type of high intensity discharge hid gas discharge lamp.
In either case the outer bulb provides thermal insulation protection from the ultraviolet radiation the.
The high pressure helps increase efficiency and this was developed in 1936 35 years after the low pressure lamps came out.
The lps lamp is also called a sox lamp so for sodium advantages.
Can be retrofitted into older mercury vapor fixtures better bulb life than lps lamps.
The energy used to make non visible light is a waste of energy since it does not help do the principle job of an electric light.
After that the lamp would heat fast and mercury became a vapor.
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.
High pressure sodium lamp hps lamp.
The heat knocks electrons out of the electrodes by thermionic emission which helps maintain the arc in many types the electrodes consist of electrical filaments made of.
A mercury vapor lamp is a gas discharge lamp that uses an electric arc through vaporized mercury to produce light the arc discharge is generally confined to a small fused quartz arc tube mounted within a larger borosilicate glass bulb.