(no subject)

[stormdog]

I am a dork...

I found someone online selling a vacuum tube that zie didn't know anything about. It was big and interesting looking, so I googled it and found the datasheet. Then I wrote the seller a note with a link to the datasheet and told zir that it's a mercury-arc rectifier tube and how awesome those are to see running.

But I have no interest in buying the thing.

Any mad-scientist types out there want to rectify some high-voltage AC in a really flashy (haha) way for some project?

Comments

[acelightning]

You've got to be careful with mercury-arc rectifiers. They give off a lot of very intense UV light; you can damage your eyes without realizing it if you look straight at one, and if you work around them, you can get sunburn, and even skin cancer, anywhere the UV shines on your skin. They were very popular for transmitter power supplies, even into the 1970s, but eventually solid-state rectifiers became capable of handling the high power involved (without the risk of mercury vapors or UV burns).

[stormdog]

Oh, I didn't realize they produced UV. Apparently a lot of people in videos on Youtube don't realize that either! I'm glad I can see them safely, albeit second-hand.

[acelightning]

That was one of the first things the guys taught me when I got a job where I had to deal with the 10KW AM transmitter. I didn't bother to tell them I can see UV (I'm a tetrachromat, which is only possible in females), because they wouldn't have believed me ;-)

[stormdog]

Oh, that's nifty! My partner has wondered whether she is a tetrochromat; her ability for color discrimination is definitely better than most. She aces all of those 'line up these colors' tests that are out there. Looking at those tests with her made me realize that I might have some small deficit in red/green discrimination. That's not too surprising, since my dad is red/green colorblind, but I hadn't noticed until we found that there were some shades that I simply see no difference in.

I found that pretty funny, given how into the production of visual artwork (via photography) that I am. But I'm more into subject and composition than color.

[acelightning]

When I was in high school, back in the Cretaceous Era, I hung out with the tech squad (although girls weren't allowed to join the tech squad). Not only did they show film strips in classes, they also ran the lights and sound in the school's auditorium. One of the theatrical productions had a song-and-dance routine in which the performers wore hats, shoes, and gloves that had been painted with fluorescent paint; for that number, the stage lights were all off, but there were UV lights amongst the footlights. I'd been watching a rehearsal, and when it was done, as we were leaving, I called out, "Hey, Richie, you left the UV lights on!" "How can you tell? You can't see the pilot light from here." "I can see the purple glow on the stage!" Up until then, I assumed that everybody could see it. The guys didn't even think it was possible, but we checked it a couple of different ways, and I really could see UV light. At the time, we didn't have the information that it was only possible for women :-)

The cone cells in the retina come in three varieties, each sensitive to a different portion of the visible spectrum (they overlap). The genes for these cells are carried on the X chromosome. The gene for the blue end of the spectrum have more variability than the other two. Women have two X chromosomes, so we can have two different forms of that type of cone cell at the same time, giving us an extended range. (Men only have one X chromosome, of course.)