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Domain: pupman.com

Stories and comments across the archive that link to pupman.com.

Comments · 8

  1. I like this one by TimeElf1 · · Score: 4, Informative · on Musical Tesla Coils Perform Zelda

    There are likely only about 1,000 Tesla coil hobbyists worldwide.

    There are quite a few more of us around as the Pupman mailing list http://www.pupman.com/ and the Geek Group http://www.thegeekgroup.org/ can attest.

  2. Re:The summary doesn't match TFA. by jeffstar · · Score: 3, Informative · on The Power Grid Can't Handle Wind Farms

    DC lines can be higher voltage than AC lines. one line is +345 kV while the other is -345kV and so you have a 700kV line without all the funny things that start to happen when you have AC lines that are 700+ kV.

    higher voltage means more power for the same current or less losses for the same power if you want to look at it that way.

    Then also since it is DC there is no capacitance and I think you get further reduction in losses from that.

    Here is a model for an AC transmission line showing all the capacitance etc

  3. Re:Not a Mirror, But Related by another_henry · · Score: 1 · on Small Change, and Other Physics Fun
    Or rather did, before they stopped doing interesting things a year or so back and started threatening to sue a guy for "stealing" an image from their website... which they turn out to have got from someone else anyway, the same guy the accused got it from!

    They are also big on posting unsubstantiated claims to the list and this has really harmed their credibility.

  4. Re:Not a Mirror, But Related by another_henry · · Score: 1 · on Small Change, and Other Physics Fun
    Or rather did, before they stopped doing interesting things a year or so back and started threatening to sue a guy for "stealing" an image from their website... which they turn out to have got from someone else anyway, the same guy the accused got it from!

    They are also big on posting unsubstantiated claims to the list and this has really harmed their credibility.

  5. Re:Not a record, but... by another_henry · · Score: 1 · on Small Change, and Other Physics Fun
    Just like to point out that although the skin effect does exist (in metallic conductors) it DOES NOT APPLY to humans. This is backed up by plenty of recent research - see the Pupman mailing list. You do not feel a shock from a Tesla coil (in theory) because the frequency is high enough that your nerves can't respond - therefore it is much less dangerous than DC or low frequency AC because there is little risk of stopping your heart. However it can and does still cause deep internal RF burns.

    Actually on one of the two occasions I took a strike from my small Tesla coil, I certainly did feel it. The ground wire came disconnected and arced through me. The other time was on purpose but I carefully stood on an insulated platform and held a screwdriver to the streamers, much reducing the risk.

  6. The Black Hole by jeffmock · · Score: 3, Informative · on Great Surplus Stores?

    I haven't been there in about four years and at the time Ed Groethus, the owner, didn't seem to be in such great health, but I think the place is still there.

    The Black Whole near Los Alamos, NM is quite a site. Most of the surplus stuff is from the nearby national lab. The place has been there maybe 40 years and is filled with crazy nuclear related stuff. Ed Groethus, the guy that owns the place seems to be very fond of much of his junk, so it can be tricky to get him to part with the good stuff.

    Everyone calls the place "The Black Hole", but I think the real name is something more boring like "Los Alamos Salvage". It's definitely worth the trip if you're within 500 miles and are mesmerized by bits of shiny metal.

    jeff

  7. Hands on science as a kid... by Powercntrl · · Score: 2, Interesting · on Hands on Science Learning

    My parents bought me one of those Radio Shack project kits that already had all the components with little springs attached to them. You'd simply hook up wires between things and let the magic smoke out. I'm sure if I had the paitence back in the day, I'd probably have actually made the AM radio transmitter and blinkenlights things like the manual said.

    It's a good thing I didn't have the Internet back then, a potato cannon or a tesla coil would have been a lot more dangerous than just a little bit of Radio Shack brand magic smoke.

  8. Try this at home! by Anonymous Coward · · Score: 0 · on Build Your Own Tesla Coil

    Those are neat pictures, but if you want to know how they are actually built, go here.