The 8533 is a forced air cooled planar triode for operation up to 3 GHz. The maximum anode dissipation is 100 Watts.
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The 8533 is designed to be used within a co-axial cavity and all connections are made to the rings with the exception of the heater connection that plugs into the base.
The thin ceramic tube envelope is 20 mm in diameter, and including the base is 68 mm tall.
Reference: Data-sheet. Type 8533 was first introduced in 1971. See also1971 adverts.