Lamps
Home Up Nature of Light Basic Illumination Concept Relationship between Luminous Intensity and Illumination Lamps Luminaires

 

4.    Lamps

Lamps are devices for obtaining light from electricity.

Lamps can be classified into 3 main categories namely: incandescent-filament lamp, gaseous discharge lamp, and mercury blended-light lamp.

(a) Incandescent-Filament Lamps (Figure 5)

Light is produced by means of a filament of carbon, tungsten, or other metals, heated by an electric current

 

Figure 5 Incandescent Lamp

(i) Higher Efficacy : the luminous efficacy is the ratio of the luminous flux emitted from the lamp to the power consumed, the unit being lumen/watt.

(ii) Longer Life : the filament in an incandescent lamp evaporates as it is heated

Incandescent-filament lamps can be further divided into two types, according to the atmosphere inside the bulb:

(i) General Lighting Service(GLS) Lamps

ii) Halogen (TH) Lamps

 

(b) Gaseous Discharge Lamps

These include high/low pressure mercury vapour lamps, high/low pressure sodium lamps, and mercury halide lamps.

(i) Low Pressure Mercury Vapour (Fluorescent) Lamps

(ii) High Pressure Mercury Lamps (MBF) (Figure 6)

Figure 6 High Pressure Mercury Lamps

 

(iii) Low Pressure Sodium Lamp (SOX)

(iv) High Pressure Sodium Lamps (SON, SON-L, SON-R)

(v) Mercury Halide Lamps (MBI)

 

(c) Mercury Blended-Light Lamps

 

Figure 7 Summary of Lamp Types & their Characteristics

 

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