@Crusty... "I only came in contact with them...." Which is still a lot more than most of us. Nice comment about the suntan.
I've watched a couple of the video links given...but none has satisfied my curiosity - what is a typical forward voltage drop for there devices?
" I wonder just how many electromechanical items we still use..." A surprisingly large number, I would say. My washing machine (+/- 10 yrs old) still has a few relays. Most household circuit breakers are still EM devices. And the average printer, of course, is full of them.
In Crusty Mansions we are almost solid state now, just a few electromechanical activators remain, I wonder just how many electromechanical items we still use, but do not notice any longer in the average home?
I have come across Mercury Arc Rectifiers in my time, as these were the main way for rectifying huge amounts of AC traction power for Londons Underground trains. Sadly I never had a qualification to work with traction power, so I only came in contact with them when it became a problem to be solved by the LTE Research Laboratory.
Brilliant things in all ways, to long with the metal doors of the cabinets open and you got a brilliant sun tan, and what an unearthly glow to walk towards.
The DC power control resistors slung under the trains were something else and I regularly used the cast iron elements for dropping power from the DC main to run some of my more arcane experiments at the Laboratory.
Yes, it's a mercury arc rectifier. When I was a kid I recall seeing one in the Scince Museum in London, and it was working at the time. Emitted a blue-green glow when it was working. The cathode was a pool of mercury at the bottom, the anodes were (I think) carbon rods in the tubes around the sides.
What are the engineering and design challenges in creating successful IoT devices? These devices are usually small, resource-constrained electronics designed to sense, collect, send, and/or interpret data. Some of the devices need to be smart enough to act upon data in real time, 24/7. Are the design challenges the same as with embedded systems, but with a little developer- and IT-skills added in? What do engineers need to know? Rick Merritt talks with two experts about the tools and best options for designing IoT devices in 2016. Specifically the guests will discuss sensors, security, and lessons from IoT deployments.