Our flicker checkers are spinning tops that have a radial pattern that shows the frequency of modulation of light, known as flicker. Students are using the devices to see if their classrooms and homes use inefficient, out-of-date electromagnetic ballasts or efficient electronic ballasts.
Osram Sylvania donated 1000 flicker checkers to EnergyTeachers.org in 2007. Flicker checkers also come in curriculum-kits from the NEED Project.
It is commonly known that fluorescent lights, and solid state lights on AC power lines, flicker. This top shows whether the flicker is a low, humanly perceivable flicker, as with the 120Hz flicker that comes from magnetically-ballasted fluorescent lamps, or the flicker is unperceived because the ballasts are modern electronic ballasts that switch at frequencies too high for humans to perceive.
Students interested in saving energy in their schools can visit classrooms with the flicker checker, spin it with their fingers on a desk or the floor, and tell interested parties whether the classroom has older ballasts or more efficient electronic ballasts. It has been said that newer ballasts cost 15% less to operate than magnetic ballasts.
- Wikipedia — Fluorescent Lighting — Flicker Problems : http://en.wikipedia.org/wiki/Fluorescent_lamp#Flicker_problems