Testing zener diodes can be a pain, so I decided to design and build this tester. I wanted it to be battery operated, chargeable, portable and simple. I think the result meets these criteria quite well.
I divided the video into two parts, with the part 1 being the build process, and part 2 covering the circuit development and design. If you don't want to waste time on design considerations, you can just follow the part 1 video. Part 2 is here: https://youtu.be/Wzr7VUXc5Vw
I decided to use simple modules that are cheap and easily available for some functions. These are often cheaper than some single components needed, so their use is actually a good idea and simplifies matters. The modules I used here are: