Charging Up Wirelessly [Circuits from a Systems Perspective]

Approximately 20–25 years ago, the consumer market experienced—for the first time—a wire-free way of charging their toothbrushes, shavers, and other small appliances almost 100 years after Nikola Tesla experimented with Tesla coils to demonstrate the possibility of transmitting electricity wirelessly. Today, inductive or wireless charging is almost ubiquitous, where integrated wireless technology is embedded into tables, drinkware, and other common household items. So how does wireless charging actually work? In this article, I briefly explore how wireless charging systems are created and some of the fundamental circuits that are key to their reliable function. But first, a short history lesson.