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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.
For example, a factory that is lit from a single-phase supply with basic lighting will have a flicker of 100 or 120 Hz (depending on country, 50 Hz x 2 in Europe, 60 Hz x 2 in US, double the nominal frequency), thus any machinery rotating at multiples of 50 or 60 Hz (3000–3600rpm) may appear to not be turning, increasing the risk of injury to ...
The advent of miniature lights found the adaptation of twinkle bulbs as flasher bulbs, which interrupt the entire series circuit of anywhere from 10 to 50 bulbs when powered from 120-volt mains electricity (in North America). These are easily recognizable by their red tips on an otherwise unpainted clear white bulb, and are available in the ...
Centennial Bulb in fire station 6. Several reasons have been cited for the bulb's extensive lifespan. Its continuous operation has largely eliminated the stresses associated with turning a light bulb on and off, the act of which causes the temperature of the bulb to increase and decrease.
Flicker at power frequency is more noticeable in the peripheral vision than it is when viewed directly. Near the end of life, fluorescent lamps can start flickering at a frequency lower than the power frequency. This is due to instability in the negative resistance of arc discharge, [74] which can be from a bad lamp or ballast or poor connection.
For flicker also two alternative measures are derived to measure its visibility, the Flicker Visibility Measure FVM and the Time domain Flicker Visibility Measure TFVM. [ 8 ] NOTE - The application of the SVM-metric is limited for human perception of stroboscopic effect in normal application environments (residential, office) where the speed of ...
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).
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]