Tube-number record
247A
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BrandWestern Electric
ClassLow-power triode
Base5-pin
Filament2 V @ 1.6 mA
Construction
Primary TypeTriode
EnvelopeGlass
SectionsSingle
Filament / Heater
Heater NotesAC or DC; Heater-to-cathode voltage should not exceed 90V.
Absolute Maximum Ratings
Plate Voltage180 V
Grid 1 Voltage-11 V
H-C Voltage90 V
Audio Performance
Power Output0.096 W
Key Features
- Indirectly heated cathode
- Low microphonic noise
- Eliminated sputtering sounds
Typical Operation
| Mode | Plate V | Gm (µmhos) | Rp (Ω) | µ | Plate mA |
|---|---|---|---|---|---|
| Typical Voltage Amplifier | 135 V | 940 | 16000 | 15.2 | 3.2 mA |
| Maximum Operating Condition | 180 V | 940 | 15700 | 14.9 | 3.6 mA |
| Typical Power Output | 150 V | 580 | 24100 | 13.9 | 1.4 mA |
Application Notes
Used as audio-frequency voltage amplifier, low-power audio amplifier, oscillator, and detector. Cathode should be connected to heater transformer center-tap to reduce hum.
Datasheets
Datasheet: 247A.pdf
Download PDFLoading datasheet...
Datasheets courtesy of Frank Philipse via Frank's Electron Tube Data Sheets.
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