Classification-Dome-type or Aubergine-type bulb of glass, a white ceramic base with four-prong bayonet gold pins , oxide coated filamentary, carbon plate triode.
Application-Audio frequency amplifier where power outputs of approximately 22.5watts or less is required at relatively low plate voltages.
Dimensions-Dimensions, outline diagrams of the tube and bases, and the arrangement of electrode connections to the base terminals are shown in Figures 1, 2 .

Nominal operating conditions and parameters

Filament voltage………………………………………………………………5 V*
Nominal filament current……………………………………………………2.4A
Plate voltage…………………………………………………………………400V
Grid voltage…………………………………………………………………－70 V**
Plate current…………………………………………………………………120 mA
Amplification factor…………………………………………………………3.85
Grid to plate transconductance …………………………………………8500 micromhos
Grid current………………………………………………………………… 0.05 μA
Plate resistance………………………………………………………………450 ohms
Load resistance………………………………………………………………2.0 kohms

*Alternating-current filament supply or Direct-current filament supply.
**Alternating-current filament supply is used. The grid and plate returns should be connected to a center tap on the secondary of the filament transformer.
***Direct-current filament supply is used. The grid and platter returns are connected to the negative end of the filament.

Characteristics-Average characteristics

Figure 3 . shown typical curves of plate currents of grid voltage for several values of plate voltages. It is alternating-current filament supply.

Limiting Operation Conditions for Safe Nor-nor simultaneous ratings

Maximum plate voltage…………………………………………………………450 volts
Maximum plate dissipation………………………………………………………80 watts