Tube-number record
8A1
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BrandBrimar
ClassR.F. Screened Pentode
BaseDecal
Filament4 V @ 1000 mA
Construction
Primary TypePentode
EnvelopeGlass
Base MaterialPlastic/Glass
SectionsSingle
Filament / Heater
Heater NotesIndirectly heated
Absolute Maximum Ratings
Plate Voltage250 V
Grid 2 Voltage100 V
Grid 1 Voltage-200 V
Cathode Current6 mA
H-C Voltage180 V
Audio Performance
Key Features
- Screened Pentode
- Indirectly Heated
- Suitable for R.F. circuits
- Recommended as anode bend detector
Typical Operation
| Mode | Plate V | Gm (µmhos) | Rp (Ω) | µ | Plate mA |
|---|---|---|---|---|---|
| R.F. Amplifier | 200 V | 4000 | 375000 | 1500 | — |
| Anode Bend Detector | — | — | 250000 | — | — |
Application Notes
It should only be used in R.F. circuits where the input does not greatly exceed 0.5 volts. As an anode bend detector, a cathode bias resistor of 8,000 ohms is recommended with a screen voltage of 60V and anode resistor of 0.25 megohms. Heater-cathode insulation is high enough for cathode coupling.
Datasheets
Datasheet: 8A1.pdf
Download PDFLoading datasheet...
Datasheets courtesy of Frank Philipse via Frank's Electron Tube Data Sheets.
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