While circuits can’t be copyrighted, they can be patented. Mats spotted this simple undervoltage indication circuit that is supposedly covered by a patent. 
via Dangerous Prototypes

More here

Related

An audiophile headphone amp for $219 (but sounds much more expensive)

(Image: Bottlehead) The Bottlehead Crack amplifier.  "This is what we call a Skill Level 1 kit, perfect for first time builders. The circuit is so simple you can build it in an evening or two. A simple circuit also means a low parts count, which keeps the price low, too.…

High-resolution microscopy advance could shrink CPUs beyond current limits

Modern life would be very, very different if it weren't for photolithography, a very simple step in the processes for making an integrated circuit. Essentially, you use a slide projector to project an image of the circuit pattern on a wafer. Exposing the wafer to a light pattern modifies a…

First ever chemical circuit could bring computing inside your body

Your body, in many ways, is a computer. It's not wired up with silicon, but relies on chemical pathways to transmit and receive information and instructions. Conventional electronics tend to not play well with biology, but the invention of the first artificial chemical circuit could be the key to interacting…