The 8639 is a 40 watt dual tetrode designed for regulator service. Similar to a 5894 with an 8 pin base. Made by Amperex.
Length = 4.92" Diameter = 1.94"
Max voltage = 4000
Max current = 220 ma
Fil voltage = 6.3 or 12.6
Fil current = 1.8 or .9 amps GOTO INDEX