Western electric 394 a brochure

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BELL SYSTEM PRACTICES SECTION A346. 394A
Transmission Engineering and Data Issue 2, October 1962
Electron Tube Data A. T.& T. Co. Standard

ELECTRON TUBE DATA SHEET
WESTERN ELECTRIC 394A ELECTRON TUBE

DESCRIPTION

The 39M! is a thre
negative control h€:§c , 2
controlled motif-150

cu;

ode ry-vapor and gas-filled thyrutron with a
This tube is designed for regulated or

1250 volts
Average Cathode Current .................... 0.6L ampere

FILE:THYRATRON SECTION

© American Telephone and Telegraph Company 1962

394A

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[31 EU}; RATINGS, Absolute Values .
Peak Anode Voltage
Inverse . . . . . . . . ............ . . . 1250 volts
Forward . . . . . . . . . . ............. 1250 volts
Cathode Current .
Peak. . . . . . . . . . . . ........... . . 2.5 amperes
Average . . . . . . . . . . ..... . . . . . . . . 0.6L ampere
Surge (maximum duration 0.1 second) ....... . . 25 amperes
Averaging Tine. . . . . . . . . . . . . . . . . . . . 5 seconds
Elegative Grid Voltage
Before Conduction . . . . . . . . . . . . . . . . . . 500 volts
During Conduction . . . . . . . . . . . . . . . . . . 10 volts
Positive Grid Current,Average(Averaging time-one cycle) 0.010 nnpere .
Condensed Mercury Temperature Limits!" -55 to +80 centigrade '

ELECTRICAL DATA
Min. m Hex.

Filament Voltage . . . . . . . . . . . . . . . . m 2.5 m volts 1
Filament Current at 2.5 Volts. ......... --- 3.25 3.50 amperes I
Filament Heating Time Required . . . . . . . . . 15 -~ -~- seconds

Anode to Grid Capacitance. . . . . . . . . . . . --~ 1.6 -- uuf.
Grid to Filament Capacitance . . . . . . . . . . --- 5.5 --- uuf.

Deionizaticn Time. :qaproxinate2
Ebb'1250 -volts;Ib-2.5 amperes;

Eco-~18 voltszTflg-SOC;Rn-ZOCOC ohms. . . . . . --- 1000 --~ microseconds
Ionization Time, Approximate3
Ebb-100 volts:TEg-L0€;Grid Cvervoltage-S volts --- 25 --- microseconds .
Ebb-100 volts;THg-800;Grid (vervoltaee-ZS volts --- 0.5 --- microseconds
Anode Voltage Drop . . . . . . . . . . . . . . . --- 15 --- volts
Critical Grid Current at 220 Anode Volts . . . . --- ~-- 5 nicroamperes
Change in Critical Grid Voltage at
500 Anode Volts from +20 to *80Tfig. . . . . . --~ 0.2 --- volts
EMMA
Type of Cooling. . . . . . . . . . . . . ....... . Convection

Equilibrium Condensed Hercury Temperature
Rise Above .-'.mbient

At Full Load (Approximate). . . . . ......... 17 Centigrade

At No load (Approximate). . ............ . 12 Centigrade .
Mounting Position. . . . . . . .......... . . . Vertical-base down
Set Weight, Approximate. . . . . . . ..... . . . . . 3 ounces

Dimensions and pin connections shown in outline drawing on Fuse L.

1. For starting conditions only. Equilibrium operation is limited to +200 minimum
condensed mercury temperature.

2. Deionization time decreases with an increase in negative grid voltage or

with a. decrease in (a) condensed mercury temperature (THE); (9) Rrid resistance
or (c) anode current immediately preceding the end of conduction. .

3. Ionization tine decreases with an increase in (a) anode voltage, (b) condensed
mercury temperature (THg) or (c) grid over-voltage. Grid overvoltage is defined
as the magnitude by which the applied voltage exceeds, in a positive direction,
the critical grid voltaae value. Critical grid voltage is the instantaneous .
value of grid voltage at the time when anode current starts to flow.