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Joined 1 year ago
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Cake day: June 13th, 2023

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  • People joke about this all the time, and I here the sarcasm in your comment, but technology has come far since the iphone 6 or 7.

    Most high end phones have wireless charging build it. Between the receiver coil and the rest of the phone is a thin sheet of ferrite material to prevent the electromagnetic field from getting to the sensitive electronics. Battery technology has also improved a lot, so much that even relatively cheap phones like the Realme GT Neo 5 charge at 150W!

    From the technical perspective the limit is the cable and connector, because there would be too much losses that heat up the cable to dangerous levels and rapidly degrade the contact area in the connectors. Manufacturers don’t want to deal with this security risk, not the increased RMA rates within the mandated guarantee period, so they artificially limit the charging rate.

    Thing is: You absolutely can charge at higher speeds if you bypass the cable altogether! A microwave outputs usually somewhere between 150W-1000W, so stick to the lower end to be on the safe side. The screen of the phone must face down, because the charging coil is placed on the back. You also must prevent overcharging by setting the timer correctly: If your phone battery has 15Wh capacity, and you are charging with 150W, you must at most charge for 1/10 of an hour, or 6 minutes (less if you are just topping up your phone).

    One final note: fast charging does put increased wear on the battery, so I only recommend to use it when you need it, for example when you need to make a flight and are already running late.


  • I am aware of the basic arguments behind inflation/deflation, and neither is good in excess.

    Typically central banks targets inflation of 2% these days, but we all know the real inflation for necessities is far higher (>4%). Inflation disproportionately affects the poorer - rich people have the fast majority of their wealth “stored” in stocks or real estate, which rise in valuation as people rush into these markets to protect the little they have. I’d argue that inflation rates are artificially pushed far higher then is sustainable, simply because those who decide are the same people who benefit the most.

    I consider a low but predictable inflation rate about 1% ideal (0-2% is acceptable short term variation) for the following reasons:

    • No one has to worry about debasing/devaluing your currency by injecting more supply.
    • Nobody “passively” gains wealth by sitting on it.
    • If you want to keep your wealth, you have to take some risk and use it.
    • Inflation rate is not so high, that you need super high risk investments to keep up, making it more accessible to small players.
    • Large player can not as easily game the market by skimming of value from the lower to upper middle class.

    Yes, this idea is not without risks. But the way I see it the forced “we have to improve value by 2% every year” exponential grow can only go on so long before we (humanity) hit the finite limits of this planet.














  • The signal does not care about how it gets from the sender to the receiver. The only thing that matters is that at the receivers end 0s and 1s can be separated. One common measurement is the eye pattern. If the eye is “open” enough (=matches the spec), communication is possible.

    Impedance mismatch causes reflections (visible as oscillation after rising/falling edge), differential pair line mismatch degrades the slop of the signal transition (rising/falling edge). Geometric features only matter if they are large compared to the signal wavelength. As a rule of thumb features smaller then 1/20th of a wavelength can be safely ignored, often times a ratio as large as 1/5 works just fine. USB3 uses 2.5Ghz (5Gbit/s) or 5Ghz (10Gbit/s), where 1/20th result in 3.4mm and 1.7mm respectively (assuming an effective dialectic of 3.17). This is still grossly simplified, because in many real systems you don’t control the entire transmission line (eg. user buys a random cable and expects it to work), so it makes sense that the USB consortium specifies eye patterns and factors in various system uncertainties.

    RAM on the other hand uses 16/32/64/128 single ended data lines, with a dedicated clock line. Data does not have to arrive perfectly at the same time, but the margin may be as little as 1/10th of a clock cycle. Here accurate length matching is absolutely required. Its also the reason why the same CPU + RAM combination may archive higher stable clock rates on some mainboards then on others.