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Portable Chargers for Your Mobile Gadgets

A selection of battery packs with enough kick to charge a tablet, plus ways to get power when completely off the grid

4 min read
photos of devices
Image: myCharge

The batteries in your smartphone, Bluetooth headset, tablet, and pocket digital camera are usually good for a full day—unless you’re using them a lot. Then, finding an AC outlet can be critical. There are a plethora of outlet-free solutions, and because the mobile electronics industry is finally making USB the standard for charging, third-party companies have been encouraged to innovate. Even Apple, which has eschewed USB sockets on its mobile products in favor of its own designs, uses a standard USB connector at the cable end that plugs into a computer or charger.

If you need to charge a tablet—the iPad can require up to 2100 milliamperes of current, roughly double what a smartphone requires—the field is narrowed significantly. Happily, there are tablet-class rechargeable power packs aplenty, with a variety of sizes, weights, capacities, and features. Here’s a look at a few that run the gamut.

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From WinZips to Cat GIFs, Jacob Ziv’s Algorithms Have Powered Decades of Compression

The lossless-compression pioneer received the 2021 IEEE Medal of Honor

11 min read
Photo of Jacob Ziv
Photo: Rami Shlush

Lossless data compression seems a bit like a magic trick. Its cousin, lossy compression, is easier to comprehend. Lossy algorithms are used to get music into the popular MP3 format and turn a digital image into a standard JPEG file. They do this by selectively removing bits, taking what scientists know about the way we see and hear to determine which bits we'd least miss. But no one can make the case that the resulting file is a perfect replica of the original.

Not so with lossless data compression. Bits do disappear, making the data file dramatically smaller and thus easier to store and transmit. The important difference is that the bits reappear on command. It's as if the bits are rabbits in a magician's act, disappearing and then reappearing from inside a hat at the wave of a wand.

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