Inside a cheap eBay mains voltage cup warmer.
On the basis that a mains / wall-power cup heater is bound to have a bit more oomph than a USB one, I decided to order one to check it out. It appears that the PTC heating device will accommodate a wide voltage range from 100V to 250V.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
http://www.bigclive.com/coffee.htm
