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Joined 3 years ago
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Cake day: June 10th, 2023

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  • Electrical Engineer here. Pretty sure the slit is to break up the metal in the card so it won’t interfere with NFC.

    If you look at an NFC antenna, it’s a big coil of wire. It’s energized by an oscillating magnetic field that passes through it. Faraday’s Law dictates that when a magnetic field oscillates, an electric field will form around it. This electric field generates a current in the antenna that powers the NFC chip.

    In a metal card, the current will flow in the card instead and draw energy away from the NFC chip. This slit blocks that current flow so that the current flows in the antenna instead.













  • A friend of mine moved to SF right out of college. A year or so later, he told me that he visited Busch Gardens Williamsburg which is a theme park near where we grew up. It was originally owned by Anheuser-Busch, so you can get beer basically anywhere in the park.

    He had this to say:

    “You know, this is the first time I’ve been since turning 21. I was surprised to see how cheap the beer was. They were only charging $8 a pint.”