The 2C40A is a UHF/SHF triode for use in grounded grid circuits up to 3.37 GHz. The given μ of the valve is 36 and the body of the valve would be enclosed in resonant cavities joined by the grid plane.
The valve is effectively split into two by the square mesh grid. The top cap leads to the anode that has a flat circular section placed just above the grid. From the base the heater produces emission from a coated cathode disc placed just below the grid.
The envelope is 6 mm diameter at the top cap, 12 mm diameter at the first glass tube, 17 mm diameter below the grid ring, 25 mm diameter at the base and 30 mm diameter just above the pins. Excluding the IO base pins it is 49 mm tall.
Reference: Datasheet. Type 2C40A was first introduced in 1961.
Absolute Maximum Operating Conditions¶
Updated February 21, 2014. construction:disc.seal.(glass) type:triode age:1960.1975 base:io heater:6.3v pins:8 pin: