Western electric 271 a brochure

Page 1

BELL SYSTEM PRACTICES SECTION AB46.27IA
TRANSMISSION ENGINEERING AND DATA ISSUE I, AUGUST I948
ELECTRON TUBE DATA A.T.&T. CO. STANDARD

moms .
POWER AMPLIFIER Western Electric

DESCRIPTION
The 271A is a power amplifier triode having an indirectly heated cathode. It is
. designed for use in amplifier, modulator, or oscillator circuits for both audio and

radio frequencies.

CHARACTERISTICS

Heater Voltage , r . . I . r . . . 5.0 volts
Maximum Plate Voltage V . i . 450 volts
. Power Output , . . i . 3.0 watts

ELECTRON TUBE DATA SHEET
FILE: GENERAL PURPOSE SECTION
12-47

Page 2

271A -- PAGE 2

GENERAL CHARACTERISTICS

ELECTRICAL DATA

Heater Voltage, A-C or D-C 5.0 volts
Heater Current , 2.0 amperes
Direct Interelectrode Capacitances (without external shield)
Grid to Plate , 4.2 uuf
Input . 6.7 uuf
Output . . . 3.1 uuf

MECHANICAL DATA

Cathode , Coated Unipotential
Bulb _ 819

Base , Medium 5-pin
Mounting Position Any

Dimensions and pin connections shown in outline drawing on Page 5

MAXIMUM RATINGS, Design-Center Values

Plate Voltage . 450 volts
Plate Dissipation 27 Watts
Plate Current 7 60 milliamperes
Heater-Cathode Voltage , 100 volts

TYPICAL OPERATING CONDITIONS AND CHARACTERISTICS - CLASS A1 AMPLIFIER

Plate Voltage , 300 350 400 450 volts

Grid Voltage -25 -25 30 -30 volts

Peak A-F Grid Voltage 25 25 30 30 volts

Plate Current 19.5 34.5 37.5 57.5 milliamperes
Transconductance 2250 2930 2920 3480 micromhos
Amplification Factor 8.2 8.4 8.3 8.5

Plate Resistance 3650 2850 2830 2450 ohms

Load Resistance , 14600 5700 6000 4900 ohms
Maximum Signal Power Output 0.9 1.7 2.4 3.1 watts

Total Harmonic Distortion 4.5 6 6 3.1 per cent