

Sure, building your own breadboard computer is much better than playing with some website… However transistors and relays are kind of similar in function, they both gate whether current flows.
If you are already familiar with transistors, then I agree those are a simpler introduction, however most regular people don’t know anything about a transistor, and they seem a little bit magical.
A relay however can be grasped by most people just by looking at it in operation. Magnet attracts… Electromagnets only attracts when powered… wire doesn’t conduct when not connected… Wire does conduct when connected… Electromagnet can pull or push wire to either connect or disconnect…
If you want the solution for the first task (building a nand gate with relays), you can see my solution here:
spoiler











You got it 😉