Tubes

I found this very interesting article on the website of G3YNH, David W Knight.

It gives an in-depth explanation on how Gas Discharge Tubes work.
One particular tube that is based on gas discharge is the Thytatron.

And as a kind of etimological revelation to me I found out that the semi-conductor known as "Thyristor" is actually coined from the combination "Thytatron - Transistor".