Western electric 426 a brochure

Page 1

BELL SYSTEM PRACTICES AB46.426A

Transmission Engineering and Data Issue 4, January 1962
Electron Tube Data A.T.& T. Co. Standard

. ELECTRON TUBE DATA SHEET
WESTERN ELECTRIC 426A ELECTRON TUBE

DESCRIPTION

The 426A is a three-electrode inert-gas-filled miniature cold cathode tube for
use in relay, voltage regulator or rectifier circuits. This tube is especially
suitable for use in control circuits such as in triggering, counting or switching

I apparatus.
CHARACTERISTICS
Peak Anode Voltage- - . - - ~ - - - . . . - - - - - 180 volts
Average Cathode Current - - - - - ~ ~ - - - - - - - 7.5 60 milliamperes
Average Life, Approximate - - . - - ~ - - - - - - -10000 10 hours

. File: Cold Cathode Section

(9 American Telephone and Telegraph Company 1962 426A

Page 2

426A - PAGE 2

MAXIMUM RATINGS, Absolute System (Note 1)

Forward Peak Anode Voltage - - - - . - - . - - . - 180 volts
Forward Cathode Current(Note m

Peak . . . . . . . . . . . . . . . . . . . 60 milliamperes
Average . . . . . . . . . . . . . . . . . . . . . 30 milliamperes
Averaging Time - - - - - - - - - - . . - - - - 2 seconds
Peak Inverse Current (Note 2)

Anode . . . . . . . . . . . . . . . . 5 milliamperes
Starter . . - - - - - - - - - . ~ - - 1 milliampere
Ambient Temperature Limits- - - - - ~ . - . - ' - - -55 to +85 centigrade

ELECTRICAL DATA, Throughout Life

Min. Bogey Max.

Starter Breakdown Voltage . . . . . . .65 72 85 volts
Starter Voltage Drop at 3 Milliamperes Anode Voltage Drop at 10 Milliamperes (Notes 4 & 5). . .63 69 75 volts
Transfer Current . . . . . . . . . . See Figure 1, Page 3

Ionization Time Starter Gap Deionization Time Main Gap. . . .- 6 - milliseconds
Inverse Current at -l20 Volts Anode Potential

MECHANICAL DATA

Mounting (Note 3) . . . . . . . . . . . . . . . . . . . . . . . Any Position
Net Weight. . . . . . . 0.7 Ounce
Dimensions and connections shown in outline drawing on page 4

HANDLING

This tube contains a small amount of krypton-85 gas which is a by-product
radioactive material. The amount of krypton-85 is less than five microcuries. which
is too small an amount to require any special care in use.

Atomic Energy Commission regulations require that the individual tube carton
for tubes containing by-product radioactive material be appropriately marked. The
marking includes the statement that tube disposal should be in approved manner.

Approved instructions for disposal of tubes containing krypton-85 are as
follows;

Tubes to be disposed of should be broken or crushed in a well
ventilated place releasing any resulting vapors to the outside
atmosphere. The residual broken or crushed tubes should be dis-
posed of in a normal public trash disposal system. Tubes should be
disposed of at a rate of not more than 100 each week from any one
location. Avoid breathing vapors from broken tubes.

Note 1: In the "Absolute System" the maximum ratings specified are limiting values above which the
serviceability of the device may be impaired from the viewpoint of life and satisfactory
performance. Maximum ratings, as such, do not constitute a set of operating conditions and
all values may not, thereforE. be attained simultaneously.

Note 2: Sufficient resistance must be used in series with the tube to assure that the electrode
currents do not exceed the maximum rated values.