Tube-number record
7A.3
0 archive entries
7A.3 is a tube type in the TubeDatabase archive (class: High Slope Power Pentode). Recorded specifications: brand Brimar, construction Pentode, socket 7-pin (non-miniature), and maximum plate voltage 250 V. The archive does not yet hold a photographed example of this type.
BrandBrimar
ClassHigh Slope Power Pentode
Base7-pin (non-miniature)
Filament4 V @ 2 mA
Construction
Primary TypePentode
EnvelopeGlass
SectionsSingle
Filament / Heater
Absolute Maximum Ratings
Plate Voltage250 V
Grid 2 Voltage250 V
Typical Operation
| Mode | Plate V | Gm (µmhos) | Rp (Ω) | µ | Plate mA |
|---|---|---|---|---|---|
| Class A | 250 V | 10000 | 60000 | 600 | 31 mA |
| Operation 2 | 200 V | — | — | — | 31 mA |
| Operation 3 | 150 V | — | — | — | 30 mA |
Application Notes
A resistor of 100 ohms is recommended in the anode circuit to prevent parasitic oscillations. Automatic bias is strongly recommended.
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