Edited by Stephen J. Mraz

A self-contained device, the PG-1 from Tellurex Corp., Traverse City, Mich. (tellurex.com), generates electricity when heat is properly applied. (The company suggests using canned fuel as a heat source.) It is designed to demonstrate the Seebeck effect, but can also be used for practical purposes, such as powering handheld electronic devices, LED arrays, and USB equipment, as well as to charge batteries, according to the company. The generator puts out 0.75 W, adjustable from 3 to 14 Vdc with a built-in voltage converter. It costs about $250.