Small dictionary of lighting terminology
What does LED mean? And what's candela? Answers to technical lighting terms are explained concisely in this small dictionary.
Lamps & Lights
Due to the small dimensions of the bulb and the filament in a halogen bulb, precise light guidance is possible, which therefore helps avoid scattered light. The small bulbs, which are available in a wide range of different models, are used in industry and trade wherever concentrated light needs to be directed at one point.
Cold light lamps
In many areas within industrial production, a uniform level of light intensity is required over an extensive area. Cold-light lamps that operate with fluorescent lamps are suitable for this purpose. This type of luminaire is used both here and internationally as the best type of assembly and machine lamp.
Fluorescent lamps are low-pressure mercury vapour discharge lamps. They can cater to approx. 70% of the total artificial light requirements, but consume only 50% of the energy used for lighting. They are comprised of a straight or curved discharge tube, the interior of which is coated with phosphors, with two tungsten filament electrodes are fused in at both ends.
Low-voltage halogen lamps
Due to their narrow beam of light, low-voltage halogen lamps allow precise focusing and optimum light guidance. They are particularly suitable for installation in very small lamps that create an accent by emitting an intense spot of light. Low-voltage halogen lamps are operated using a conventional (magnetic) or electronic transformer. There are different product series available, which are characterised by their suitability for either the commercial-professional market or the consumer market.
This is used to describe the amount of luminous flux that strikes any given surface. More precisely, illuminance is the quotient of luminous flux and surface area. If, for example, a luminous flux of 1000 lumen falls uniformly on a surface measuring 5 m2, this produces an illuminance of 200 lux. The eye's ability to see properly primarily depends on the level of illuminance.
Candela is the measure for light intensity. Or for short: cd.
A diffusion filter scatters the light from a light source.
This is the abbreviation for electronic ballast unit. Also see ballast.
Describes the colour impression from a lamp.
Warm light =< 4000 K
Cold light => 4000 K
Legal temperature unit. Also used to indicate temperature differences. Named after William Thomson, who later became Lord Kelvin, and who introduced the thermodynamic temperature scale in 1848.
The greater the light efficiency of a lamp, the more economically the lighting can be implemented. Light efficiency is calculated based on the luminous flux emitted and the electrical power required to produce it. Conventional incandescent bulbs generally exhibit an efficiency between 6 and 15 lm/W, while fluorescent bulbs reach 40 to 100 lm/W.
The light intensity describes the amount of light that is emitted in a specific direction in the room. However, the luminous intensity of a bulb or lamp is not equal in every direction. If the light intensities in a room (or on level surfaces) around the bulb or lamp are measured, the light intensity distribution can be obtained, which precisely describes the photometric properties.
Unit of measurement for indicating the luminous flux emitted by a lamp.
Unit of measurement for specifying the illuminance.
Point light source
A point light source is described as a point in the room which emits light.
The mechanical, thermal and technical safety requirements for lamps are described in detail in international and European standards. Standard EN IEC 598 (Luminaires – General requirements and tests) is the most authoritative. Compliance with this standard ensures that lamps are designed so that they do not endanger the safety of people, pets and goods, as long as they are installed, maintained and used as intended. The requirements serve in preventing:
- Electric shock in the event of contact
- Lamp malfunctions
- Reduced service life of bulbs and lamps
- Ignition of fires by bulbs and lamps in their surroundings
The protection class is specified by the marking (VDE, SEV, ÖVE, KEMA). The protection class indicates how the luminaire is protected against electric shock (short circuit) (EN IEC 598). The assignment is indicated using Roman numerals or pictograms.
They refer to:
I. Operational insulation and protective earthing of all conductive parts that can be touched
II. Functional insulation and additional protective insulation, no protective earthing
III. Activated and powered by protective and extra-low voltage (max. 50 V)
Unlike incandescent bulbs, discharge lamps must be operated with a ballast due to their negative current-voltage characteristics. A conventional ballast unit is comprised of inductance coils which, when the appropriate starting aids such as glow starters are used, provide a sufficiently high ignition voltage and limit the lamp current.
Perception refers to how a stimulus is sensed: the ears hear sounds, the nose smells odours, and the skin feels temperature and touch. The specific properties of the light and the way the eyes function, in turn, determine perception and the way the light stimuli are processed. Any light stimulus simultaneously functions as colour stimulus. By principle, the following prerequisites make good perception possible:
- The object must exhibit a certain degree of minimum contrast compared to its environment (contrast in brightness or colour)
- An object must have a certain minimum size
- There must be a specific minimum density of light (object and/or surroundings)
- The eye must adapt to the prevailing light density within the field of vision
- The object must be located within the field of vision of the observer for a sufficient period of time
- The eye must be fully functional (correction of impaired vision)
- The observer should not be too fatigued
- The observer must be in a good state of mind (i.e. not mentally ill)