The superior efficacy and greater light
output make the hot-cathode (“fluorescent”)
lamp more suitable in almost all lighting
applications; hot cathode lamps are the prin-
cipal light source for lighting building interiors.
Fluorescent lamps are usually identified by an
“F” followed by wattage, shape, bulb diame-
ter in eighths of an inch, and color (phosphor
kind and correlated color temperature). For
example, F32T8/RE830 is a 32 W, 1-in-
diameter, fluorescent lamp with rare-earth
phosphors and a correlated color tempera-
ture of 3000 K (figure 7.3).Lamp-ballast circuits
Fluorescent lamps require a ballast to regu-
late the electric current through the lamp.
Three kinds of fluorescent lamp-ballast cir-
cuits are made: preheat, instant-start, and
rapid-start.Figure 7.3Fluorescent lamp shapes and sizes at one-eighth actual size.