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In visual perception, flicker is a human-visible change in luminance of an illuminated surface or light source which can be due to fluctuations of the light source itself, or due to external causes such as due to rapid fluctuations in the voltage of the power supply (power-line flicker) or incompatibility with an external dimmer.
A street lamp mounted on a bracket and column A high pressure sodium street light fixture. Street light interference, sometimes called high voltage syndrome, is the claimed ability of individuals to turn street lights or outside building security lights on or off when passing near them. [1]
Temporal light artefacts (TLAs) are undesired effects in the visual perception of a human observer induced by temporal light modulations. Two well-known examples of such unwanted effects are flicker and stroboscopic effect. Flicker is a directly visible light modulation at relatively low frequencies (< 80 Hz) and small intensity modulation levels.
Furthermore, external factors such as incompatibility with dimmers or presence of mains-supply voltage fluctuations (power-line flicker) play a role and may cause additional temporal light modulations. TLMs can be designed-in fluctuations from the electronic driver because of application of certain driver or light-regulation technologies.
A thyristor dimmer rack An electrical schematic for a typical SCR-based light dimmer Solid-state , or semiconductor , dimmers were introduced to solve some of these problems. Semiconductor dimmers switch on at an adjustable time (phase angle) after the start of each alternating-current half-cycle, thereby altering the voltage waveform applied ...
Dimming technologies of either externally applied dimmers (incompatible dimmers) or internal light-level regulators may have additional impact on the level of stroboscopic effect; the level of temporal light modulation generally increases at lower light levels. NOTE – The root cause temporal light modulation is often referred to as flicker.
The rest of the road is still covered in bright light with just a pocket of dimmer light around the other vehicles. This way a deer, pedestrian or bicyclist by the side of the road can still be ...
The requirements of a flicker measurement equipment are defined in the international electro-technical standard IEC 61000-4-15. [2]A flickermeter is composed of several function blocks which simulate a 230 V/60 W or a 120 V/60 W incandescent lamp (reference lamp) and the human perception system (eye-brain model).