Table of Contents Walk through any electronics store, peek behind any desk, or open up any tinkerer’s parts bin, and you’ll find them: DC barrel jack connectors. These simple, cylindrical connectors are the primary way millions of devices—from internet routers and guitar pedals to LED lights and older laptops—receive their power. Despite the modern dominance of USB, the humble DC barrel connector remains a workhorse in the industry. It’s cheap, robust, and capable of handling significant power. However, it also carries a legacy of confusing standards that has frustrated consumers