Tube-number record
281
0 archive entries
281 is a tube type in the TubeDatabase archive (class: Rectifier). Recorded specifications: construction Rectifier, socket 4-pin, and maximum plate voltage 700 V. The archive does not yet hold a photographed example of this type.
ClassRectifier
Base4-pin
Construction
Primary TypeRectifier
Rectifier TypeVacuum
EnvelopeST-19
SectionsSingle
Filament / Heater
Absolute Maximum Ratings
Plate Voltage700 V
Cathode Current85 mA
Audio Performance
Key Features
- Directly heated filament
- High voltage half-wave rectifier
Typical Operation
| Mode | Plate V | Gm (µmhos) | Rp (Ω) | µ | Plate mA |
|---|---|---|---|---|---|
| Half-wave Rectifier | 700 V | — | — | — | 85 mA |
Application Notes
The 281 is a half-wave vacuum rectifier designed for use in power supplies of early radio receivers. It is equivalent to the 81 tube.
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