5
Light sources
Light can be produced from electricity in several ways and the most important are:
- Incandescence Light and infrared energy are produced by raising the temperature of a substance (e.g. tungsten) until it is incandescent.
- Electrical discharge Light is produced by electricity passing through a gas or vapour, agitating or exciting the atoms of the filling to produce light, UV energy and infrared energy.
- Fluorescence and phosphorescence The process by which UV energy is converted into visible light by phosphors.
Source |
Lumens per watt |
100W household lamp |
13 |
3200 K tungsten halogen lamp |
26 |
HF fluorescent lamp |
80 |
HID lamp 6000 K |
95 |
Table 5.1 Output as a percentage of input power
3200 K Incandescent lamp |
|
Losses ... | |
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