Following the voltage letter, " A " stands for a low-current ( signal ) diode section, " B " for a double diode with common cathode section, " C " for a triode section, " F " for a pentode section, " H " for a hexode or heptode section, and " L " for a power tetrode or pentode section.
12.
Two or more elements in a single envelope were handled by adding letters after the heater identifier, in alphabetical order, so an ECH35 is a 6.3 volt heated triode plus a hexode with an octal base; a PABC80 is a Noval 300mA series-heater combination of a single low-power diode A, a pair of diodes with common cathode B, and a triode C . There were many ECCnn ( n ) 6.3V dual triodes.
