General Electric Lighting introduced a dimmable compact fluorescent bulb on Thursday that mimics the performance of old incandescent bulbs. The bulb, with a re-engineered ballast, can be dimmed smoothly to 5 percent of its full power and light, just as the old incandescent bulbs do. The CFL spiral is available in 14-watt and 26-watt versions, producing the light of 60-watt and 100-watt incandescent bulbs, respectively, and rated to last 10,000 hours. The bulb is also available as a dimmable reflector flood light in 15-watt and 26-watt versions, rated to last 8,000 hours. A...