Western electric 348 a brochure

Page 1

BELL SYSTEM PRACTICES AB+6.31+8A
Transmission Engineering and Data ISSue 2, February 1956
Electron Tube Data A.T.&T. Co. Standard

ELECTRON TUBE DATA SHEET
WESTERN ELECTRIC 348A ELECTRON TUBE

DESCRIPTION

The 3h8A is an indirectly heated cathode type pentode having a separate

suppressor grid connection. It is intended for use in audio, carrier and radio-

. frequency voltage amplifiers, oscillators or modulators. It has special design
features to minimize microphonic noise and hum. This tube, except for having a

different base, top cap, heater voltage and current rating, is identical to the

310B.
CHARACTERISTICS
Heater Voltage . . . . . . . . . . . . . . . . . . . . . . 6.3 volts
Plate Current . . Eb = 180 volts; E02 = 135 volts; . . 5.5 milliamperes
. Transconductance . Eel = -3 volts; Ec3 = O 1820 micromhos

File: General Purpose Section
Issue 3, 2-56

348A

Page 2

shaA - Page 2

GENERAL CHAMCTEEBTICS

ELECTRICAL DATA

HeaterVoltage...........

Heater Current . . .
Direct Interelectrode Capacitances

C-rid to Plate (maxim) . . .

without
external
shield

Input: g1 to (h+k+g2+g3+i.s.) . . . . . .

tput: p to (he-k+g2+g3+i.s.) .

IECEAIUCAL 31115.

Cathode . . . . . . . . . . . . . .
Bulb . . . . . . . . . . . . . .
Base . . . . . .

Mounting Position . . . . . . . . .

O .016

6.0
13

6.3 volts
0 . 50 ampere
with
external shield
(RETHA #311)

*0.010 ppf
*7.0 our
*13 Hui

Coated unipotential
STIZ
Small, 7-pin octal
Any

Dimensions and pin connections shown in outline drawing on page) 5

MAXIMUM RATINGS, Design-Center Values

PlateVoltage . . . . . . .
Screen Gr1d Voltage . . .
Plate Dissipation . . .
Screen Grid. Dissipation .

Cathode Current . . . .
Heater-Cathode Voltage

TYFICAL OPERATING COIIDITIOXS ART) CHARACTERISTICS

Plate . . . . . . . . . . . . . . .
Screen Grid Voltage . . . . . . . . .
Control Grid Voltage . . . . . . . .
Suppressor Grid Voltage . . . . . . .
Plate Current . . . . . . . . . . .
Screen Grid Current . . . . . . .
Peak A-F Signal Voltage . . . . . .
Plate Resistance . . . . . .
Iransconductance

Load Resistance . . . . . . . .
Power Output .

Total Harmonic Distortion

Control Grid Voltage, Approximate, for

Plate Current of 10 Microanzgeres -

. . 135
. . 135
. . -3
. . o
. 5.40
1.20

. . 3.00
. . 0.75
1800

. . 20000
. . 250
8.5

. . -9.5

180

-3

U1 U1
80.6300

5-
1.
1.
o.

1820
100000

150
6

-9-5

250 volts
180 volts
2.0 watts
OJ; watt
10 milliamperes
30 volts

250 volts
135 volts
-3 volts
0 volts
5.60 milliamperes
1.17 millianrperes
2.10 volts
1.15 megohms
lBhO micromhos
100000 ohms
310 milliwatts
6 per cent

-9.5 volts

*With exteer shield (RETMA #311.) connected to cathode pin.