<< 274B 274A 274B/n 274A /n Vacuum Tube





Classification- Dome-type or Aubergine-type bulb of glass, a white ceramic base with four-prong bayonet golden pins, oxide coated filamentary, Solid plate or mesh plate twin diode.

Application -It is designed to supply direct current up to 112 miliamperes from an alternating current soure.

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* 5.0V
Nominal filament current 2A

Choke-Input filter
RiM-S Alternating voltage prelate 550V
Tolal rectified current 112mA

Condenser-Input Filter
RiM-S Alternating voltage prelate 450V
Tolal rectified current 98mA

*Alternating-current filament supply or Direct-current filament supply.

Characteristics-Average characteristics
The current-voltage characteristic of a single diode untie of the 274A /B tube is shown in Figure 4. Direct-voltage output characteristics are given in Figures 5 and 6. The characteristics of figure 5 are for a choke-input filter such as is shown in circuit A and those of Figure 7 are for a condenser-input filter such as is shown in circuit B.

Limiting Operation Conditions for Safe Nor simultaneous ratings

Choke-input filter:
1 Max. R-M-S alternating Voltage per plate 550 volts
1 Max Total Rectified Current 140 mA
2 Max. R-M-S Alternating Voltage per plate 660V
2 Max. Total Rectified Current 120mA

Condenser-input Filter:
1 Max.R-M-S Alternating Voltage per plate 450V
1 Max. Total Rectified Current 105mA

*4uF.Maximum filter input capacitance