:56291327 About my tunnel diode blog - I am suing the free Google blog service called "Blogger".  You can see that I have a couple of other old, out of dated Blogger blogs, mainly on Rpi experiments.   These couple of years I am using rpi.org/blog.  It is good for projects: Relay Module KY-019 5V - tlfong01, www.raspberrypi.org/forums/projects/automation,sensing, and robotics
https://www.raspberrypi.org/forums/viewtopic.php?f=37&t=77158#p1323061. The good thing of this kind of project blogs is (1) You can start a project, or just exploring something, say, I did not know anything about relay, so I joined the discussion on relays.  I just want to explore relays, and the discussion can go freely to any where, as you can see if you follow my posts.