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Cake day: June 4th, 2024

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  • gnu@lemmy.ziptoScience Memes@mander.xyz*Permanently Deleted*
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    2 months ago

    I remember one time when I was a kid and had read something mentioning spark gap transmitters. I of course found a bit of wire (tie wire because that’s what came to hand, not anything insulated) and a radio and was playing around with a 9v battery making little sparks by shorting it with the wire and hearing the radio crackle in response. What I then thought was that if the little battery was making a noticeable effect then a bigger battery would obviously be better.

    I got one of the drill batteries and shorted that out with my bit of wire to make a better spark and proceeded to discover that resistive heating is a thing and thin tie wire connected even briefly to a high discharge battery will get very hot very quickly. I ended up with a nice blister line across my fingers and a scar for a few years showing the position I’d been holding the wire…


  • gnu@lemmy.ziptoScience Memes@mander.xyz*Permanently Deleted*
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    8 months ago

    The primary factor is that 120mm is not the actual focal length of the lens in the phone, that will be a considerably smaller focal length that happens to give the same field of view as a 120mm lens on a full frame camera (i.e. the same sensor size as a 35mm film frame). The phone uses a much smaller sensor than this hence the smaller focal length for the same FoV.

    Another thing that helps is using a telephoto lens design - including this lets you create a lens noticeably shorter than its focal length.

    When the lens would still make an overly wide phone despite all this that’s where the periscope lens design as others have already mentioned comes in.



  • It’s high quality comedy from Terry Pratchett and Neil Gaiman. The base idea being that the biblical antichrist and final battle is real and approaching but the angel and demon who are meant to be leading the battle between good and evil have decided that after thousands of years on earth they’re actually ok with the status quo.

    It’s also a TV series which was a reasonable adaptation (at least the first series, haven’t watched past that) but the book is as usual superior.