Flicker
Flicker refers to light output fluctuations caused by varying supply voltages, such as those occurring in the 230V AC low-voltage grid. In LED technology and with the drivers used (notably simple transformers where measurable flicker is more pronounced), these fluctuations are very high-frequency and cannot be detected by the naked eye.
The LED chips used by LED2WORK are all equipped with technical components for stabilizing the luminous flux and compensate for power-supply voltage variations across wide input-voltage ranges. These ranges are specified for each fixture.
Stroboscopic Effect
Conventional light sources often operate directly on the mains voltage and therefore run at a frequency of 50 Hz. The current changes direction 100 times per second. The resulting light pulses at a speed that is not perceptible to the human eye. This can make rotating parts appear stationary when illuminated. When our LED chips are powered by regulated switch-mode power supplies and are not dimmed via pulse-width modulation, a stroboscopic effect can be excluded. This makes our fixtures suitable for camera applications, such as those used in optical inspection.
Flicker Noise
In technical terms, flicker noise refers to luminance fluctuations that are not caused by the supply voltage but are generated by the internal design of the light source itself.
Nearly all light sources we use are equipped with continuously operating linear regulators to stabilize and control the supply currents, instead of fast-switching components known as switch-mode converters, which could generate additional flicker.
Metrics and EU regulation: PstLM, SVM and Eco-Design
Since the EU Regulation 2019/2020 (Eco-Design regulation for lighting, applicable from 1 September 2021), the following limits are legally binding for mains-operated LED light sources:
- PstLM ≤ 1.0 — assesses perceptible flicker intensity at low modulation frequencies. PstLM (Short-Term Flicker Severity) is the standardised measure of visible light flicker. Values ≤ 1.0 are considered not perceptibly disturbing to humans.
- SVM ≤ 0.4 — assesses the stroboscopic effect at higher frequencies (visibility on moving objects). SVM (Stroboscopic Visibility Measure) for unobtrusive lighting is typically below 0.4.
These limits apply to every light source newly placed on the EU market. Datasheets from reputable industrial manufacturers state the measured values for both metrics explicitly. At workstations with rotating or fast-moving machinery, SVM should be well below the regulatory maximum in practice in order to reliably avoid the stroboscopic effect.