Beam Angle
The angle over which a luminaire distributes its light. Wide beam angles provide broad illumination, while narrow beam angles create accents.
LED Glossary
Technical Terms from A to Z.
Concise, easy-to-understand explanations for planning, purchasing, installation and maintenance.
A
AC/DC
Alternating current and direct current. Some Schmelter products are designed for both operating modes.
B
Operating Hours
The period for which a product operates under defined conditions. Service-life specifications always depend on the operating environment.
C
CRI / Ra
A measure of colour rendering. The higher the value, the more naturally colours appear under the light source.
D
DALI
A digital control protocol used to switch, dim and monitor compatible luminaires and control gear.
Direct Mains Connection
Operation of an LED tube or luminaire without the existing ballast. Any rewiring must be carried out professionally and in conformity with applicable requirements.
E
EMC
Electromagnetic compatibility. Equipment must not cause unacceptable interference and must provide sufficient immunity to electromagnetic disturbances.
Electronic Control Gear (ECG)
Electronic control gear for fluorescent tubes. It operates at high frequency and differs technically from magnetic and conventional ballasts.
F
Colour Temperature
Specified in kelvin. Lower values appear warmer, while higher values appear cooler or more similar to daylight.
G
G5
A two-pin base with 5 mm pin spacing, typically used for T5 tubes.
G13
A two-pin base with 13 mm pin spacing, typically used for T8 tubes.
H
HE / HO
T5 designations for High Efficiency and High Output. Tubes of the same length may have different wattages.
I
IK Rating
Indicates the resistance of an enclosure to mechanical impact.
IP Rating
Describes protection against contact, solid foreign objects, dust and water. The two digits must be interpreted separately.
K
Kelvin
The unit used for colour temperature, for example 3000 K warm white and 4000 K neutral white.
Magnetic Ballast
A conventional magnetic ballast, generally used together with a starter in fluorescent lighting systems.
L
LED Starter
A bridging element used with certain LED retrofit tubes in magnetic-ballast luminaires. It is not a conventional fluorescent starter.
Lumen
The luminous flux emitted by a light source or luminaire. Lumen describes the total amount of visible light emitted.
Lux
Illuminance on a surface. One lux is equal to one lumen per square metre.
O
Obsolescence
The unavailability of a component or product even though the higher-level installation is intended to remain in service.
R
Retrofit
Modernisation of existing technology using compatible replacement or conversion solutions without replacing the complete system.
S
SELV
Safety Extra-Low Voltage with safe electrical separation, typically used for protection class III.
SI4 Technology
Universal SUPERIS technology for different connection types, AC/DC operation, electronic control gear, magnetic ballasts and direct mains connection, depending on the specific product version.
Surge
A short-duration overvoltage event caused, for example, by switching operations or other transient events.
T
T5
A tube family with a diameter of approximately 16 mm, generally using a G5 base.
T8
A tube family with a diameter of approximately 26 mm, generally using a G13 base.
Thermal Management
Design measures used to limit and dissipate heat so that LEDs and electronic components operate reliably.
LED Driver
Electronic control gear that supplies LEDs with the appropriate current or voltage.
U
UGR
A rating method for psychological glare in indoor environments, relevant to lighting design and luminaire selection.
V
Low-Loss Magnetic Ballast
A low-loss magnetic ballast similar to a conventional magnetic ballast, but with reduced power losses.
W
WEEE
Marking and regulatory framework for the separate collection and disposal of waste electrical and electronic equipment.
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