TUBE: WE418A (418A)
FICHIER SOURCE: sheets/084/4/418A.pdf
FABRICANT: Western Electric (Bell System Practices, A.T.&T. Co. Standard)
ANNÉE: April 1956 (Issue 1; File Issue 2, 4-56)
PAGES: 4

===== PAGE 1 =====
BELL SYSTEM PRACTICES
Transmission Engineering and Data / Electron Tube Data
AB46.418A — Issue 1 April 1956 — A.T.&T. Co. Standard
OFFICIAL FILE COPY

ELECTRON TUBE DATA SHEET
WESTERN ELECTRIC 418A ELECTRON TUBE
[photo of 418A tube]

DESCRIPTION
The 418A electron tube is an indirectly heated cathode type tetrode. This tube
was designed primarily for use as a power output tube in broad-band video and inter-
mediate-frequency amplifiers.

CHARACTERISTICS
Heater Voltage ........................ 6.3 volts
Cathode Current (Eb = Ec2 = 150 volts) ... 70 milliamperes
Transconductance (Ec1 = 0, Rk = 27 ohms) ... 26500 micromhos

File: General Purpose Section / Issue 2, 4-56

===== PAGE 2 =====
418A - Page 2
GENERAL CHARACTERISTICS

ELECTRICAL DATA
Heater Voltage ... 6.3 volts
Heater Current ... 0.6 ampere
Direct Interelectrode Capacitances (Without External Shield):
  Grid to Plate ............... 0.055 µµf
  Input: g1 to (h+k+g2+i.s) ... 15.0 µµf
  Output: p to (h+k+g2+i.s) ... 2.8 µµf

MECHANICAL DATA
Cathode ... Coated Unipotential
Bulb ...... T9
Base ...... See outline drawing page 4
Mounting Position ... Any

MAXIMUM RATINGS, Design Center Values
Plate Voltage ............ 250 volts
Screen Grid Voltage ...... 150 volts
Plate Dissipation ........ 8.5 watts
Screen Grid Dissipation .. 3.0 watts
Control Grid Dissipation . see footnote * (positive grid operation not recommended)
Cathode Current .......... 90 milliamperes
Heater-Cathode Voltage ... 90 volts
Bulb Temperature ......... 130 centigrade

MAXIMUM CIRCUIT VALUES
Grid Circuit Resistance:
  For Fixed Bias ... 0.05 megohm
  For Cathode Bias . 0.10 megohm

TYPICAL OPERATING CONDITIONS AND CHARACTERISTICS   (col1 / col2)
Plate Voltage .................. 120 / 150 volts
Screen Grid Voltage ............ 120 / 150 volts
Control Grid Voltage ........... -1.0 / --- volts
Cathode Bias Resistor .......... --- / 27 ohms
Plate Current .................. 47 / 50 milliamperes
Screen Grid Current ............ 20 / 20 milliamperes
Plate Resistance ............... 18000 / 18000 ohms
Transconductance ............... 26500 / 26500 micromhos
Control Grid Voltage (approx.) for Plate Current of 10 microamperes ... -9.5 / --- volts

* Operation with the control grid positive with respect to the cathode is not recommended.

===== PAGE 3 =====
[courbes seules — pas de données tabulaires]
Page 3 - 418A. Plate-current and screen-current characteristics vs plate voltage at Ec2 = 90, 120, 150 V (Ec1 steps 0 to -4); plus Ip and screen current vs control grid voltage at Eb=Ec2 = 90/120/150 V. Ef = 6.3 V.

===== PAGE 4 =====
[courbes seules — pas de données tabulaires]
Page 4 - 418A. Transconductance (gm) and plate resistance (rp) vs control grid voltage at Eb=Ec2 = 90/120/150 V, Ef=6.3V.
Outline drawing: T9 BULB; dims 1-3/16" max dia, 1-31/32" max overall, etc.
VIEW A-A basing (9-pin, T9): Pin1=PLATE; Pin2=HEATER; Pin3=NO CONNECTION; Pin4=CATHODE AND INTERNAL SHIELDS; Pin5=SCREEN GRID; Pin6=HEATER; Pin7=NO CONNECTION; Pin8=CONTROL GRID; Pin9=CATHODE AND INTERNAL SHIELDS.
(pinout: pin1=a; pin2=h; pin3=nc; pin4=k,is; pin5=g2; pin6=h; pin7=nc; pin8=g1; pin9=k,is)
A development of Bell Telephone Laboratories.