I’ve been working at teaching myself some basic electronics as a hobby. I’ve had some successes with very small scale things (eg: Pi —> I2C —> GPIO expander —> relays. I’m starting to get closer to higher power stuff (eg 5A @ 5V for powering a 256 neopixel array). Given the currents involved, I’d like to get a second set of eyes on the schematic — I’d like to learn from my mistakes without committing to releasing factory installed magic smoke from me or the boards I will eventually make.

Is there a place where I can go, share my schematics or schematic fragments, and get useful-to-me feedback? What kinds of tools are used? How do I “show my work” (show how I calculated resistor values, etc.) in a way which is helpful to reviewers?