Researchers at the Virginia Commonwleth University have come up with . . . a circuit that requires such little power all it needs is the ambient energy in an environment to run. In other words, it can run without need of a power lead or battery, relying instead on some energy constant in the environment in which it functions e.g. the human body. In order to create something that can run on such low, ambient energy, you need to use electronics that require next to no power to function. So instead of the typical charge-based electronic switches used today, the researchers turned to spin transport electronics, more commonly known as spintronics.