Quote:
Originally Posted by Fred
I never thought about that...the neutral gas making thermal isolation.
cool 
regards,
Fred. |
Not cause it's inert chemically ...but cause of very low pressure... yes it is... cause density isn't enough for good thermal exchange...
Indeed, some so-called "vacuum-tubes" are not in hi vacuum but with small pressure of inert gases... like argon.
An example is thyratron but some e.g. voltage regulators uses neon or gas mixtures at different pressures, depending e.g. on current they must carry.
Usually vacuum tubes are fairly the best choice for stability in tube oscillators but special kind filled with few inert gas (at very few pressure) or mercury vapours are suitable and even more stable cause of internal design. Many of them (also very small size for portable devices) were made by Raytheon.
Kind regards,
Max