Western electric 349 a 2 brochure
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Page 1
BELL SYSTEM PRACTICES SECTION AB46.349A
TRANSMISSION ENGINEERING AND DATA ISSUE 1, NOVEMBER 1948
ELECTRON TUBE DATA A.T.&T. C0. STANDARD
PENTODE Western Electric
DESCRIPTION
The 349A is a suppressor grid, power pentode with an indirectly heated cathode.
It is designed for use as an audio-frequency power amplifier in Class A1 and ABl
service.
CHARACTERISTICS
Heater Voltage . . 6.3 volts
Plate Current . 32.5 milliamperes
Eb = E: : 250 volts; .
Transconductance 4250 micromhos
Ed = -14 volts
Power Output 3.5 watts
ELECTRON TUBE DATA SHEET
F-IéLE: GENERAL PURPOSE SECTION
1 8
Page 2
349A - PAGE 2
GENERAL CHARACTERISTICS
ELECTRICAL DATA
Heater Voltage, A-C or D-C 6.3 volts
Heater Current . . . . , , .0 . . . . 1.0 ampere
Direct Interelectrode Capacitances , Without with
external shield external shield
(RMA $311)
Grid to Plate 0.46 *0.31 uuf
Input 11.2 >311.7 uuf
Output , 8.1 *10.5 uuf
MECHANICAL DATA
Cathode . Coated unipotential
Bulb . . , , ST12
Base . . . . . , Small shell octal
Mounting Position Any
Dimensions and pin connections shown 1n outline drawing on Page 7
MAXIMUM RATINGS, Design-Cenler Values
Plate Voltage . 250 volts
Screen Grid Voltage 250 volts
Plate Dissipation 12 watts
Screen Grid Dissipation 3.5 wars
Cathode Current . 50 milliamperes
Heater-Cathode Voltage . 150 volts
TYPICAL OPERATING CONDITIONS AND CHARACTERISTICS
SINGLE TUBE AMPLIFIER-PENTODE CONNECTION
Plate Voltage , 180 250 250 volts
Screen Grid Voltage , , , . 180 250 250 volts
Control Grid Voltage , -8 -l4 . . . volts
Cathode Resistor . . . . . . 330 ohms
Peak A-F Grid Voltage , . , 8 10 10 volts
Zero Signal Plate Current 28.0 32.0 32.0 milliamperes
Maximum Signal Plate Current , . . . 29.5 34.0 30.5 milliamperes
Zero Signal Screen Grid Current 6.0 6.5 6.5 milliamperes
Maximum Signal Screen Grid Current 8.2 11.0 10.5 milliamperes
Transconductance . 4100 4250 4400 micromhos
Plate Resistance , 70000 84500 75000 ohms
Load Resistance 5000 7000 7000 ohms
Maximum Signal Power Output 1.8 3.6 3.3 watts
Total Harmonic Distortion 6.3 8.0 8.8 per cent
3 With external shield (RMA #311) connected to cathode pin.