The Philco 615 is a small high frequency triode in an unusual multiple anode envelope. The 615's most obvious feature is its distinctive symmetrical twin anode caps, which makes the tube look like a prop for an evil robot in a Buck Rogers serial. Though this tube has an octal base, only three of its eight pins are connected internally; the grid and plate connections both exit the tube through the twin anode caps. The 615 can operate at frequencies up to 300 megahertz.
Versions of this tube were also manufactured by Hytron and National Union, with the part numbers NU615 and HY615 respectively. The Hytron version of this tube abandons the phenolic base of the more common Phico variant for one made of metal, dropping several of the superfluous octal pins in the process.
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