Western electric 427 a brochure

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BELL SYSTEM PRACTICES SECTION AB46.427A
Transmission Engineering and Data Issue 3, October 1962
Electron Tube Data A.T.& T. Co. Standard

ELECTRON TUBE DATA SHEET
WESTERN ELECTRIC 427A ELECTRON TUBE

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Harri/c

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427A2

3

DESCRIPTION

The 427A is a three-electrode inert-gas-filled cold cathode tube designed for
use as a voltage regulator and has characteristics which are exceptionally stable
with life and with variation in ambient temperature. The third electrode is pri-
marily a starting element.

CHARACTERISTICS

Cathode Current - - . . - . . - - - . - - - . - - - - -5 to 40 milliamperes
Anode Voltage Drop (Etd) - - - - - - - - - - ~ - - - - - . 100 volts
Regulation at 5 to 40 milliamperes d-c (Note 6). - . - - - - - $1.5 volts

File: Cold Cathode Section
© American Telephone and Telegraph Company 1962

427A

Page 2

427A- PAGE 2
RATINGS, Absolute System (Note u

Cathode Current, Forward

Maximum - - - - - - - - - - . - - - - - - 40 milliamperes
Minimum - . - - - - - - - . - - - - - - - 5 milliamperes
Starter Current, Forward

Maximum - - . - - - . - - - - - - - ~ - - 5 milliamperes
Minimum Maximum Inverse Starter or Anode Current - . - - - - ~ 0.0 milliampere
Ambient Temperature Limits . - - - - ~ . , . - -55 to +85 centigrade

ELECTRICAL DATA
- Mm. Bogey Max.

Anode Breakdown Voltage . . . - 165 - volts
Anode Voltage Drop (Etd) at 40 Milliamperes, (D- C)(Note 3) , 99 100 103 volts
Regulation (5 to 40 Milliamperes, D- C)(Notes 4 a 6). . . . ' --0.3 1L1.5 volts
Starter Breakdown Voltage. . . . . . . 115 125 135 volts
starter Voltage Drop at 5 Milliamperes, (D- C) . , . . , 100 110 120 volts
Transfer Current. . . . . . . . See Curve - Figure 1
Temperature Sensitivity, Anode Voltage Drop

Anode Current, 5 milliamperes (D- C) . . . . . . . . . ' -0.007 - volt/c
Anode Current, 40 milliamperes (D-C). , . . . . . . . - -0-004 - volt/c
LIFE DATA

starter Breakdown Voltage (Max.) after 500 hours at 40 mAdc. . . . . . .135 volts

Regulation (5 to 40 mAdc) after 500 hours at 40 mAd0(Note 6). . See Figure 3, Page 4
Drift 1n Anode Voltage Drop (Eta) in 500 hours at 40 mAdc. . See Figure 2 and Note 5

MECHANICAL DATA

Mounting Position . . . . . . . . . . . . . . . . . . . . . AILY
Net Weight, lApproximate- - - - - - - - - - - - ' - - - - - 0 4 Ounce
Base , - - - - - - - - - - - - - - - - - - Small Button 9- -pin
Bulb . . . . . . . . . - . T6_1/2

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.