Help Needed : A USB 5V Electric Heater Circuit

After searching much on google i came across this forum, with high hopes of finding some guide to a USB 5V Electric Heater. Any Ideas ?

The USB specification only sources a max of 500 mA per port. You're not going to generate much heat from that. Attempting to draw too much current from the USB port may cause serious damage to your computer. You'll get more heat from the cooling fans than anything you can hook up to the USB port.

I would certainly look for a better source of power than a USB port. A 9V battery might work much better and less risk of damaging your computer.

Good luck.
Michael

yeah true. but the basic idea of a project is to stick to USB lets say i want to make a USB Cup Warmer to maintain my TEA or Coffee temperature... although the requirement is not to dissipate much heat to boil water but just to keep it warm...

Thank You.

Amongst the various laws of physics and electronics, power is the product of voltage and current. Hence, 5 volts at 500 mA will yield just shy of 2.5 watts. My coffee cup warmer draws about 17 watts and just barely keeps my coffee warm. I think you are going to fall a little short of your goal. Granted, light bulbs are not necessarily the best heat source, but good enough for comparison purposes. You will basically be attempting to keep your coffee warm by the heat of one or two miniature Christmas tree light bulbs.

Let us know how that works for you.