Portable Crank

Approximately how much energy can be generated from a portable hand-crank device?

I've seen a few kinds of emergency radios (like the ones that NPR stations give away during pledge drives).. and I was wondering how much energy could be generated by hand operated devices? Do radio have such low power requirements that hand cranks are convenient? Or can other devices be used with hand cranks.. and if so, what kind of devices..? Not laptops, but.. phones? not (really) flashlights, but maybe simple calculators?

This model can generate up to 10V and 300 mA

http://scientificsonline.com/product.asp?pn=3038029&bhcd2=1174201504

You can also make your own!

http://www.creative-science.org.uk/gen1.html

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