Nuvistor type 6CW4, the most produced type, on a coin of two euros
A nuvistor is the designation of a miniature vacuum electron tube and was marketed by RCA (Radio Corporation of America) in 1959. A nuvistor is made entirely of metal and ceramic and is approximately 2 cm long. The most produced type is a triode and a smaller number of tetrodes. During the manufacturing process, the tube was not pumped after the mechanical part of the mechanical part and then fused, as happened to the conventional vacuum tube. Production instead took place entirely in a vacuum chamber. Nuvistors had and have good characteristics for VHF and UHF applications.
The nuvistor was introduced as a competitor of the transistor. Transistors were small and used little energy but were inferior to the electron tube in terms of amplification of high frequencies (MHz) and noise factor. The nuvistor united all the benefits. When the transistors became better, the nuvistor lost the battle.
The novelist is still considered for highly specialized use in a radioactive environment and / or use in a high temperature environment (typically several hundred degrees).
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