The leads of the switch must be handled carefully to prevent breaking the glass envelope.

He had to bash off four lugs, then break the glass envelope around the inner assembly.

A crack in the glass envelope will allow air into the tube and destroy it.

It can usually be seen as a silvery metallic spot on the inside of the tube's glass envelope.

He had a special bulb made with a metal plate sealed into the glass envelope.

The glass envelope has one or more arms with graphite rods as anodes.

It was observed that under some conditions the glass envelope would itself glow at the positive (anode) end.

If the outer glass envelope is damaged, a dangerous implosion may occur.

However, the glass envelope of the tube began to glow at the anode end.

When too much energy is used for the pulse duration, structural failure of the glass envelope can occur.