Classification- Dome-type or Aubergine-type bulb of glass, a white ceramic base with four-prong bayonet golden pins, oxide coated filamentary, mesh plate or carbon plate triode. Application -Audio frequency amplifier where power outputs of approximately 3.5 watts 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 and 3.
Nominal operating conditions and parameters Filament voltage* …………………………………………………………… 2.5V Nominal filament current …………………………………………………… 2.5A Plate voltage ………………………………………………………………… 250V Grid voltage** ……………………………………………………………… -45V Plate current ………………………………………………………………… 60mA Plate current ………………………………………………………………… 62.5mA Amplification factor …………………………………………………………… 4.2 Grid to plate transconductance …………………………………………… 5.25mA / V Grid Current ………………………………………………………………… 0.05 μA Plate resistance …………………………………………………… ………800 ohms Load resistance …………………………………………………………… 2.5kohms *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 4. shown typical curves of plate currents of grid voltage for several values of plate voltages. It is alternating-current filament supply. 
Fig. 4Limiting Operation Conditions for Safe Nor simultaneous ratings Maximum plate voltage …………………………………………………… 300 volts Maximum plate dissipation …………………………………………………… 15 watts
