The CF185 is a De Forest triode.
This triode was made during WWI for the Navy. This valve was not particularly suited to military use due to the fragility of the glass frame for the grid. The Western Electric VT-1 was better due to rugged construction.
The base has three sub pins 3 mm long set at the points of an equilateral triangle. This was known as the 3-pin Navy Base. There is a pip on the side of the base to give locating details. Such pins are normally held in side entry spring clips.
Within the envelope the anode consists of two rectangular plates held at three points each either side of the grid, and 4 mm away from the grid. The wire grid is formed on a notched rectangular glass support. The filament is a single strand formed into an inverted 'V'.
Of the operating details of this bright emitter we only have that the filament current was not to exceed 0.85 Amps.
The wide glass tube envelope is 28 mm in diameter and, excluding the base pins, is 103 mm tall.
References: Private communication & 1047. Type CF185 was first introduced in 1915.
Absolute Maximum Operating Conditions¶
Updated September 21, 2020. shape:wide.glass.tube construction:pinch type:triode age:pre.1920 base: pin: