Data set 01
1956 Western Electric Tubes
Published operating points and test conditions from this source.
SECTION 1
Triode
Characteristics
Typical Plate Voltage
135 V
Typical Plate Current
2.8 mA
Other
Maximum Power Output
0.035 W
ClassA
Voltage - Triode (single) ·Triode
347A
Western Electric heater-cathode general-purpose triode with amplification factor around 15.7, intended for conventional small-signal amplifier and electronic circuit service.
Directly heatedCold cathodeCommon cathodeDissimilar
- Sections
- 1
- Base
- -
- Socket code
- IO
- Base pins
- 8
- Nominal heater
- 6.3 V / 500 mA
Description
The Western Electric 347A is a heater-cathode general-purpose triode with amplification factor about 15.7.
Socket description
International Octal
General specifications
Tube and section characteristics
Properties common to every published source and operating point.
Heater and base
- Base
- -
- Socket code
- IO
- Base pins
- 8
- Nominal heater voltage
- 6.3 V
- Nominal heater current
- 500 mA
- Parallel heater voltage
- -
- Parallel heater current
- -
- Series capable
- No
Terminal pinout
Electrical assignments shared by every tube using this base designation.
No verified pinout is recorded for this base designation.
Section ratings
1 physical section, each with unique specifications.
Section 1
Triode
X-ray radiationInterelectrode capacitances
- Plate resistance
- 19800 Ω
- Transconductance
- 0.00078 S
- Amplification factor
- 15.5
- Max plate voltage
- 200 V
262B/347A shared electrical characteristics. Representative point: 120 V plate, -4.5 V grid, 2.1 mA. Maximum operating points extend to 180 V.
Source-dependent data
Operating conditions by source
Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.
Data set 02
2026 Western Electric 200s
Published operating points and test conditions from this source.
SECTION 1
Triode
Capacitance
Grid To Plate Capacitance
1.9 pF
Grid To Cathode And Heater Capacitance
2.3 pF
Plate To Cathode And Heater Capacitance
4.1 pF
Other
Maximum Heater Cathode Voltage
30 V
Plate Current
2.1 mA
PlateVoltage=120V;GridBias=-4.5V
HumOutputLevel
-116 dB re 1mA
PlateVoltage=135V;GridBias=-4.5V;Load=15kohm;SupplyFrequency
MicrophonicNoiseOutput
-54 dB re 1V
PlateVoltage=135V;GridBias=-4.5V;Load=100kohm
Data set 03
2026 Western Electric 300s
Published operating points and test conditions from this source.
SECTION 1
Triode
Characteristic
Typical plate current
2.8 mA
PlateVoltage=180V;GridVoltage=-7.5V
Other
Microphonic noise mean level
-54 dB
PlateVoltage=135V;GridBias=-4.5V;LoadResistance=100000ohm