There are a large number of tube varieties and uses.
Suddenly you’re no longer in an intimate setting, just the two of you.
You’re surrounded by strangers in halogen lighting, and it all just seems so public!
On most tubes, the leads are designed to plug into a tube socket for easy replacement.
The simplest vacuum tubes resemble incandescent light bulbs in that they have a filament sealed in a glass envelope which has been evacuated of all air.
A third element called a "control grid" can be added to the design which provides the ability to amplify a signal.