Well, yes I know how it worked. They were used in variable speed drives in a paper mill (and other applications). I replaced them as thyristors took their place. Completely replaced and with much high powers. For example often £20,000 current ratings. Some I did were up to £70,000 Amps.
I am also addicted to Youtube. I watch all sort of things, from wildlife to cartoons.
My favourites at present are Wildlife Aid with Simon Cowell & Minuscule. I also enjoy clips from Good Omens, Merlin & other films. Lots of bands/singers. I could go on & on.
Valve Doonican? 
I used to enjoy watching a chap, whose name I can’t remember now.
He used to experiment with electrical equipment, tending to overload things to destruction.
He’d do things that no-one in their right mind would go near!
I wish I could remember his name or the name of his video series.
Wonderful stuff, you can see them ripped apart on YouTube
One of my more recent interests are people living on those narrow boats on the English canals. There are many but this particular bloke is a TV journalist and his videos are quite entertaining.
It is odd how I watch these thing because as I said before boats and the sea have never interested me but boating on a canal or river even less - so restricted and all those weirs and locks would drive me to distraction. Yet I enjoy watching these videos.
My interest will eventually wane and move on to something else but there are so many fascinating topics to browse.
Not exactly huge…but interesting.
You like something huge? Well, how about these?
See? There’s something for everybody on YouTube.
If that’s what floats your boat…
That would sink a lot of Boats.
Glad you enjoyed it.