Me too. Many times. I think that my first few Gilbert chemistry sets even contained a small vial of mercury. I also played closely with a "nuclear energy" set as a young teenager that included several sources of alpha, beta, and gamma emitters. I also probably fried my feet to a crisp in the shoe store fluoroscopes in the early 1950s.
I'm in my mid-60s with no evidence of radiation damage or mercury poisioning.
This is not to say that mercury and ionizing radiation are not dangerous, or that what we did is safe. But it seems that the current hyperventilation over avoiding mercury levels that are only a small fraction of what we experienced might be an over-reaction.
Not only that, but the increased power consumption of regular incandescents over the consumption of CFLs causes the coal-burning power station to emit more mercury.
Next time Electronic ballasts contain a small circuit board with rectifiers, a filter capacitor and usually two switching transistors connected as a high-frequency resonant series DC to AC inverter. The resulting high frequency, around 40 kHz or higher, is applied to the lamp tube.
Also noted of late, cfl's I've bought have been little hummers. Can't recall in early ones. Maybe it's the cheap Walmart stuff I bought.
Like other fluorescents, the mercury is mostly liquid when the tube is off. Starts on something more like argon. Heat from running vaporizes the mercury (which is why they may not be full brightness at start). The mercury arc produces a lot of UV, which the phosphors convert to visible light.
Other than the orange neon color ones, "neon" lights work the same, with cold (not heated) cathodes.
Switch mode power supplies, like in a computer, seem to be winding up everywhere.
According to the above link, this LED bulb consumes 8.6 watts to produce 429 lumens (49.9 lumens/watt).
That is not much less efficient than a 40W-equiv. CFL, which produces
450-500 lumens from 9 watts (50-55.5 lumens/watt).
As for why this LED achieves about 50 lumens/watt while there are now LEDs achieving 100-120 lumens/watt: I doubt the reason is filters:
1: My guess is that this LED bulb is a warm white one rather than a cool white one. Warm white LEDs produce less green spectral content and more red spectral content than cool white ones do. Not only is human vision less sensitive to red than to green, but also phosphors have higher "Stoke's loss" in producing red than in producing green light from the same LED chip.
2: The LEDs in this bulb may be high color rendering index ones. There is a recent trend for "warm white" LEDs used in lighting to have color rendering index of at least 80. Cool white LEDs of extremely high efficiency have CRI only 70 to low 70's, with some having extreme lumen/watt phosphors only achieving CRI in the 60's. Higher CRI requires the phosphor's spectral band to be wider, to include a fair share of wavelengths from slightly bluish green to mid-red. This is as opposed to a narrower phosphor band concentrating on wavelengths from slightly yellowish green to slightly orangish red. The wider band has more spectral content at deeper red wavelengths that human vision is less sensitive to, resulting in less lumens per watt.
3: The LEDs in this bulb may be less efficient than the most efficient ones available of a given color and color rendering index. The most efficient available LEDs have higher cost.
4: The LEDs in the LED bulb require a "ballast" or "driver circuit", for similar reasons to the ones why a CFL requires a ballast (included in usual screw-base CFLs). The ballast has some loss. When a 120V AC-powered "LED driver" has 91 or 92% efficiency, that is getting to be something to boast about. Merely fullwave- rectifying 120 volts AC to DC has a loss around 1.5%.
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