Definition and measurement of voltage flicker (in lighting)

The level of annoyance suffered by consumers due to lighting flicker is dependent on the amplitude, shape and repetition frequency of the voltage changes which cause it. The quantification of such disturbances in terms of consumer annoyance proved difficult in the past due to the lack of an agreed definition. This has recently been overcome by the acceptance by the IEC of a definition of flicker severity. This defines the threshold of flicker perceptibility for 50% of the population in terms of percentage amplitude modulation on a 50 Hz carrier using a 60 Watt 240 volt tungsten filament coiled-lamp.