• 0 Posts
  • 42 Comments
Joined 1 年前
Cake day: 2024年2月1日
  • qjkxbmwvz@startrek.websitetoFunny@sh.itjust.works•Infinite energy trick
    51·
    12 天前

    Is that true though? As in, is it really that dangerous? It seems that you’ll dissipate power equal to the inefficiency times the nominal charging power, so something like 5V x 2A x inefficiency (inefficiency being 1-efficiency), which will probably be of order a watt.

    I can use my car battery to charge itself without any issues — I just plug the red terminal to itself, and same with the black, which is to say, a battery is always connected in a way that “charges itself.”

    I think the key is that the battery probably isn’t really playing a big role in OOP’s setup — electricity doesn’t “go through the battery,” it just goes from the charging input to the power output circuits, with the additional power (due to inefficiency) being provided by the battery.

  • qjkxbmwvz@startrek.websitetoFunny@sh.itjust.works•Infinite energy trick
    471·
    12 天前

    I’m not sure though — the power output and the charging input are both regulated and (almost certainly) current limited. So I think (not positive…) that you’re basically dissipating your power in the inefficiency the charging and output circuits, with this power coming from the battery.

    The inefficiency should (I think…) just be the round-trip inefficiency of the charging/discharging of your power bank — this should be way, way less than the short-circuit power dissipation.

    The simplest toy model is to take a battery and try to charge itself. So you put jumpers on the + terminal and you connect those to the + terminal, and same for - (charging is + to +, NOT + to -). But this is silly because you’ve just attached a loop of wire to your terminals, which is equivalent to doing nothing. With charging circuits in between things get much more complicated, but I’m not sure if it goes full catastrophic short…

  • qjkxbmwvz@startrek.websitetoFunny@sh.itjust.works•Ever been judged by a floor?
    18·
    15 天前

    For 75kg (roughly average South Korean male weight) and 7" step height (standard in the US I think, not sure about Korea), this is about 0.13kJ/step.

    By coincidence, the human metabolic efficiency is (roughly) the same as the conversion between kJ and food (kilo)calories, meaning this would be (very roughly) 0.1 calories/step.

    Not much, given a single French fry is maybe 5-10 calories. But it’s better than nothing!

  • qjkxbmwvz@startrek.websitetoFunny@sh.itjust.works•Vroom vroom!
    31·
    1 个月前

    Hmmm, I’m not sure I understand…

    A large explosion every second has units of power, not energy. So to me this is suggesting that the train is putting out power equal to its kinetic energy per second. That’s certainly not the case — it implies that the train is powerful enough to accelerate to the speed in 1s, which is definitely not true.

    But that’s just my interpretation.

  • qjkxbmwvz@startrek.websitetoMildly Infuriating@lemmy.world•Young Frankenstein is not available for streamingEnglish
    0·
    2 个月前

    Hmm, my understanding was that FQDN means that anyone will resolve the domain to e.g. the same IP address? Which is the case here (unless DNS rebinding mitigations or similar are employed) — but it doesn’t resolve to the same physical host in this case since it’s a private IP. Wikipedia:

    A fully qualified domain name is distinguished by its lack of ambiguity in terms of DNS zone location in the hierarchy of DNS labels: it can be interpreted only in one way.

    In my example, I can run nslookup jellyfin.myexample.com 8.8.8.8 and it resolves to what I expect (a local IP address).

    But IANA network professional by any means, so maybe I’m misusing the term?

  • qjkxbmwvz@startrek.websitetoMildly Infuriating@lemmy.world•Young Frankenstein is not available for streamingEnglish
    0·
    2 个月前

    If you have your own domain name+control over the DNS entries, a cute trick you can use for Jellyfin is to set up a fully qualified DNS entry to point to your local (private) IP address.

    So, you can have jellyfin.example.com point to 192.168.0.100 or similar. Inaccessible to the outside world (assuming you have your servers set up securely, no port forwarding), but local devices can access.

    This is useful if you want to play on e.g. Chromecast/Google TV dongle but don’t want your traffic going over the Internet.

    It’s a silly trick to work around the fact that these devices don’t always query the local DNS server (e.g., your router), so you need something fully qualified — but a private IP on a public DNS record works just fine!

  • qjkxbmwvz@startrek.websitetoPrivacy Guides@lemmy.one•Google Photos/Gmail AI data removalEnglish
    6·
    8 个月前

    You may want to check local regulations — if there’s a legal requirement to delete the data, I’d try to take advantage of that.

    On a related note, I cannot recommend Immich enough! I had previously used other self hosted solutions but Immich is just fantastic — great desktop and mobile, awesome locally run ML, great shared link support, an overall awesome experience. (I’m not affiliated at all. Bit of a “gateway drug” to self hosting…)