Simple USB Charger
This is simple but very powerful USB charger project for your gadget like mp3 player, camera, cell phone, and any other gadget you can plug into a USB port to charge. Main component of the project is LT1302, Micropower High Output Current Step-Up Adjustable and Fixed 5V DC/DC Converters from Linear.
The charger circuitry and 2 AA batteries fit into an Altoids gum tin, and will run your iPod for hours, 2.5x more than you’d get from a 9V USB charger. You can use rechargeable batteries too. I think this powerful USB charger suitable people who often work in outdoor place or when you are going to traveling.
Portable Charger
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