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I took a much needed vacation and didn’t post an “everything’s flipped” last week. Your topic suggestions have been good, but I haven’t had time to research. I find that writing these is a good constructive way to release my frustrations with the world. This week’s topic is light bulbs.

The Phoebus cartel existed from 1925-1939. They set a target lifespan of 1000 hours for light bulbs. The justification for this was that a hotter filament produced a higher quality light and was more efficient. I don’t have the time to find out whether the trade off between bulb costs and energy costs actually benefited the consumer. Most likely not. We perceive light in a logarithmic fashion. If the bulb lasted twice as long and used the same energy we would save money. We’d just deal with a bulb that’s slightly dimmer.

• The incandescent bulb ban is annoying as the bulbs can be used for many other things than lighting. The old HP audio oscillator used the negative resistance of a light bulb to regulate the oscillator amplitude. They make nice dummy loads that even shows you how much power is flowing. Sometimes you want to heat something, like an easy bake oven.

• Incandescent bulbs emit a lot of near-infrared light. When exposed to near-infrared light, the mitochondria produce melatonin. One paper acknowledged the difference in lighting but thought that the intensity of light from indoor incandescent lamps was not sufficient to make a difference. Since the bulbs are banned and not simply taxed to make them more expensive than LEDs….

Fluorescent lamps are have been the standard at schools and workplaces because of their higher efficiency. I can’t stand the light from these things. Fluorescent light is suspected to cause or aggravate many mental and visual disorders. The spectrum from these bulbs looks nothing like a black body. Thankfully many big box stores are installing skylights.

They contain a small amount of mercury. A Tesla coil can light a fluorescent tube from a distance. I suspect some types of Directed Energy Weapons would do the same. Note that bulbs in a fixture are partially shielded by the metal box of the fixture. The old T12 tubes are banned as well as some other types.

Many LED bulbs die prematurely from heat. If you have an enclosed light fixture with 2 LED or CFL bulbs consider this. How long does the first bulb last? How long does the second last? Most likely the second bulb alone will continue to operate for a very long time. It’s running in a cooler environment now.

Many of the new LED fixtures are basically disposable. However, they should last much longer than LED bulbs in old fixtures since they should be designed to properly cool the LEDs. The Dubai lamp is a super efficient LED bulb that uses many LED filaments to reduce the temperature rise. The cooler LEDs are more efficient and last longer.

The LED street lights are replacing the orangeish high pressure sodium lamps. This is annoying for astronomers as the LEDs are broadband emitters compared to a few spectral lines from the sodium lamp. The could use filters to reduce the specific wavelengths emitted by sodium lamps. They tell us to avoid blue light before bed, but then they put it in the streetlights. Some of those lights emit almost purple light.

Incandescent bulbs are nearly perfect resistors and have a power factor near 1. LED bulbs can have a much lower power factor and produce harmonics.

Unless we are going to run everything on batteries, there is not much reason to reduce the energy consumption of overnight lighting. You’ve seen stores keep their lights on all night. Overnight electricity is cheap.