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Power - Triode (over 1000V 100W) ·Triode

212D

Large transmitting power triode intended for RF amplifier and oscillator service, with manufacturer data emphasizing high plate voltage, substantial dissipation, and power output. It also supports power-frequency applications where documented.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
JUMBO4B
Base pins
4
Nominal heater
14 V / 6 A

Description

Air-cooled general-purpose filamentary triode for audio-frequency power amplifier and modulator service.

Socket description

Super Jumbo 4-pin bayonet

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
JUMBO4B
Base pins
4
Nominal heater voltage
14 V
Nominal heater current
6 A
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

Terminal pinout

Electrical assignments shared by every tube using this base designation.

No verified pinout is recorded for this base designation.

Section ratings

1 physical section, each with unique specifications.

Section 1

Triode

X-ray radiationInterelectrode capacitances
Plate resistance
2000 Ω
Transconductance
0.008 S
Amplification factor
16
Max plate voltage
2000 V
Max plate dissipation
275 W
Max cathode current
300 mA

Promoted fields mapped from published ratings/characteristics; additional published values preserved in parameter table.

Source-dependent data

Operating conditions by source

Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.

Data set 01

2026 Western Electric 200s

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

  • Filament Voltage

    14 Volt

    Filament Voltage 14 Volts A. C.

  • Nominal Filament Current

    6 Amperes

    Nominal Filament Current 6 Amperes

  • Average A m p l i fi c a t i o n Factor

    16

    Average A m p l i fi c a t i o n Factor 16

  • Average Plate Resistance

    2000 Ohms

    Average Plate Resistance 2000 Ohms

  • Average Mutual Conductance

    8000 Micromhos

    Average Mutual Conductance 8000 Micromhos

  • With a plate voltage of

    1500 volt

    With a plate voltage of 1500 volts grid potential at —60 volts and

  • a filament voltage of

    14 volt

    a filament voltage of 14, the plate current will be as follows:

  • FILAMENT VOLTAGE,EA«

    14 VOLT

    FILAMENT VOLTAGE,EA« 14

  • Normal fi l a m e n t current

    6 amperes

    Normal fi l a m e n t current 6.0db0.3 amperes

  • Normal fi l a m e n t voltage

    14 volt

    Normal fi l a m e n t voltage 14 volts

  • Normal plate current for plate voltage

    1500 volt

    Normal plate current for plate voltage 1500 volts and grid voltage—60 volts... 130 milliamperes

  • Normal plate voltage

    1000 volt

    Normal plate voltage 1000 to 1500 volts

  • Normal grid voltage

    -30 volt

    Normal grid voltage —30 to —80 volts

  • Normal plate to filament impedance under conditions: plate voltage

    1500 volt

    Normal plate to filament impedance under conditions: plate voltage 1500

  • volts, grid voltage

    60 volts

    volts, grid voltage—60 volts and plate current 130 milliamperes 2000 ohms

  • Output as unmodulated oscillator

    250 watts

    Output as unmodulated oscillator 250 watts

  • With a plate voltage at

    1500 volt

    With a plate voltage at 1500 volts, the grid potential at —60 volts and the filament voltage

  • should be kept as low as possible to secure the desired output and should not exceed

    14 volts

    should be kept as low as possible to secure the desired output and should not exceed 14 volts,

  • since an increase of

    10 volt

    since an increase of 10% in the voltage may shorten the life by as much as 50%.

Other

  • Maximum Plate Voltage

    2000 Volt

    Maximum Plate Voltage 2000 Volts

  • Maximum Plate Current

    300 Ampere

    Maximum Plate Current . 300 Ampere

  • Maximum safe plate voltage

    2000 volt

    Maximum safe plate voltage 2000 volts

  • Maximum safe intermittent output

    250 watts

    Maximum safe intermittent output 250 watts

  • Maximum safe continuous output

    200 watts

    Maximum safe continuous output 200 watts