The last vacuum tube

Many people no longer have tube radios in their living room, but still use vacuum tubes in their homes for lighting. This article in the Minnesota Star Tribune says that often Edison light bulbs are the last vacuum tubes left in people's homes. I thought that was interesting.

There's been a few breakthroughs since Edison bulbs were invented. Lighting by cheap compact fluorescent bulbs are usually more efficient by 4:1. And now they come in all kinds of interesting shapes, including the bulb at left that is the same shape as an old light bulb. This is useful if you have a lampshade that clips on top of an old school bulb.

And now the new LED lighting is much more efficient still than that. It's still expensive, but the price is dropping by 20% a year.

The LED bulb on the left is interesting because it constantly changes color. Try that with an incandescent bulb. It consumes only 3 watts and puts out a good amount of light for the energy used. One of the most interesting applications of LEDs will be turning the walls of a building into a large video screen. Bridges are being illuminated with colored lights in Philadelphia and New York that change colors and consume the same energy as a toaster and a hair dryer.