Classification- Dome-type bulb of glass, a white ceramic base with four-prong bayonet golden 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* ………………………………………………………… 5V Nominal filament current …………………………………………… …… 2.4A Plate voltage ………………………………………………………………… 400V Grid voltage** ……………………………………………………………… -70V Plate current ………………………………………………………………… 120mA Amplification factor …………………………………………………………… 3.85 Grid to plate transconductance …………………………………………… 8.5mA / V Grid current ………………………………………………………………… 0.05 μ A 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.
Fig. 3 Limiting Operation Conditions for Safe Nor simultaneous ratings Maximum plate voltage ………………………………………………… 450 volts Maximum plate dissipation …………………………………………… 80 watts
