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Power - Triode ·Triode

203A

Thoriated-tungsten transmitting power triode for Class C oscillator and RF power-amplifier service, with additional transmitting applications. Rated for about 100 W plate dissipation and kilovolt-level plate operation.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
J4
Base pins
4
Nominal heater
10 V / 3.26 A

Description

The RCA 203A is a thoriated-tungsten transmitting power triode. The supplied source provides transmitting, RF, or rectifier ratings appropriate to this device.

Socket description

Jumbo 4-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
J4
Base pins
4
Nominal heater voltage
10 V
Nominal heater current
3.26 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
6000 Ω
Transconductance
0.0042 S
Amplification factor
25
Max plate voltage
1250 V
Max plate dissipation
100 W
Max cathode current
175 mA

Maximum ratings and characteristic constants promoted where reliably published in the approved sheet.

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

1938 RCA Transmitting Tubes

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • filament type with a maximum plate dissipation rating of

    100 W

    filament type with a maximum plate dissipation rating of 100 watts for class C

  • D-C Plate Voltage 1000

    1250 V

    D-C Plate Voltage 1000 1250 Volts

  • Peak A-F Grid-to-Grid Voltage ... 310

    330 V

    Peak A-F Grid-to-Grid Voltage ... 310 330 Volts

  • D-C Plate Voltage

    1250 V

    D-C Plate Voltage 1250 max. Volts

  • D-C Plate Current

    150 mA

    D-C Plate Current 150 max. Milliamperes

  • Peak R-F Grid Voltage- 95

    90 V

    Peak R-F Grid Voltage- 95 90 Volts

  • D-C Plate Current... 130

    106 mA

    D-C Plate Current... 130 106 Milliamperes

  • D-C Grid Current (Approx.) 5

    3 mA

    D-C Grid Current (Approx.) 5 3 Milliamperes

  • Power Output (Approx.) - 40

    42.5 W

    Power Output (Approx.) - 40 42.5 Watts

  • D-C Plate Voltage

    1000 V

    D-C Plate Voltage .. 1000 max. Volts

  • D-C Grid Voltage

    -400 V

    D-C Grid Voltage .. -400 max. Volts

  • Peak R-F Grid Voltage ........ 235

    275 V

    Peak R-F Grid Voltage ........ 235 275 Volts

  • D-C Plate Current ........ 150

    150 mA

    D-C Plate Current ........ 150 150 Milliamperes

  • D-C Grid Current (Approx.) .. 50

    50 mA

    D-C Grid Current (Approx.) .. 50 50 Milliamperes

  • Grid Resistor ... .. 2000

    2700 Ω

    Grid Resistor ... .. 2000 2700 Ohms

  • Driving Power (Approx.) .. 12

    14 W

    Driving Power (Approx.) .. 12 14 Watts

  • D-C Plate Voltage

    1250 V

    D-C Plate Voltage .. 1250 max. Volts

  • D*C Plate Current

    175 mA

    D*C Plate Current ............... 175 max. Milliamperes

  • Plate Input

    220 W

    Plate Input-- 220 max. Watts

  • D'C Plate Voltage...... 750 1000

    1250 V

    D'C Plate Voltage...... 750 1000 1250 Volts

  • Peak R-F Grid Voltage ... 195 225

    255 V

    Peak R-F Grid Voltage ... 195 225 255 Volts

  • each stated value of grid voltage should be decreased by

    7 V

    each stated value of grid voltage should be decreased by 7 volts and the circuit returns made to the

  • For high-frequency operation above

    15 MHz

    For high-frequency operation above 15 megacycles, see page 144.

Data set 02

193X Taylor Transmitting

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • Filament Voltage

    10 V

    Nominal published value

  • Filament Current

    3.85 A

    Nominal published value

  • Maximum Operating Plate Voltage

    1500 V

    Class C oscillator / RF power-amplifier service where published

  • Maximum Plate Dissipation

    100 W

    Published maximum rating

  • Plate to Grid, mmf

    14 pF

    Published direct interelectrode capacitance

  • Plate to Filament,

    7 pF

    Published direct interelectrode capacitance

Characteristics

  • Plate Resistance

    6000 ohm

    Published general characteristic

  • Mutual Conductance

    4200 µS

    Published general characteristic

  • Amplification Factor

    25

    Published general characteristic

Data set 03

1940 Taylor Tubes

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristics

  • Plate-to-grid capacitance

    14 pF

  • Grid-to-filament capacitance

    8 pF

  • Plate-to-filament capacitance

    7 pF

Data set 04

1945 United Electronics

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristics

  • Filament voltage

    10 V

  • Filament current

    3.26 A

Other

  • Maximum direct plate voltage

    1250 V

  • Maximum plate dissipation

    100 W

  • Maximum direct plate current

    175 mA

Data set 05

1956 RCA Transmitting Tubes

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • Maximum Plate/Inverse Voltage

    1250 V

    Source rating

  • Maximum Plate Dissipation

    100 W