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Voltage - Triode (single) ·Triode

4021C

Directly heated low-impedance oxide-filament triode with top-cap grid connection and published audio operating, output, and harmonic-performance data.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
B4
Base pins
4
Nominal heater
4 V / 250 mA

Description

Standard Valves 4021C is an oxide-coated directly heated triode. The sheet publishes its filament rating, static constants, interelectrode capacitances, and a table of typical anode/grid/load operating conditions with output and harmonic performance. Oxide-coated filament low-impedance triode, medium 4-pin bayonet-thrust base with grid connected to top cap.

Socket description

European 4-pin base

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
B4
Base pins
4
Nominal heater voltage
4 V
Nominal heater current
250 mA
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
0.003 S
Amplification factor
6

Published ratings/characteristics promoted; remaining useful source values represented as parameters.

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

1937 Standard Valves

Published operating points and test conditions from this source.

SECTION 1

Triode

Capacitance

  • Grid-Anode Capacitance

    9.7 pF

    Published specification

  • Anode-Filament Capacitance

    5.5 pF

    Published specification

  • Grid-Filament Capacitance

    7.3 pF

    Published specification

Characteristics

  • Characteristic Anode Current

    23 mA

    For impedance/amplification factor/transconductance values

Other

  • Output Power

    140 mW

    TypicalOperatingConditions; PlateVoltage=130V; GridBias=-8V; AnodeCurrent=22.5mA; AnodeResistance=2050ohm; LoadImpedance=2050ohm

  • Total Harmonics Below Fundamental

    27 dB

    TypicalOperatingConditions; PlateVoltage=130V; GridBias=-8V; AnodeCurrent=22.5mA; AnodeResistance=2050ohm; LoadImpedance=2050ohm

  • Output Power

    100 mW

    TypicalOperatingConditions; PlateVoltage=130V; GridBias=-8V; AnodeCurrent=22.5mA; AnodeResistance=2050ohm; LoadImpedance=4100ohm

  • Total Harmonics Below Fundamental

    31.5 dB

    TypicalOperatingConditions; PlateVoltage=130V; GridBias=-8V; AnodeCurrent=22.5mA; AnodeResistance=2050ohm; LoadImpedance=4100ohm

  • Output Power

    87 mW

    TypicalOperatingConditions; PlateVoltage=130V; GridBias=-8V; AnodeCurrent=22.5mA; AnodeResistance=2050ohm; LoadImpedance=6150ohm

  • Total Harmonics Below Fundamental

    35 dB

    TypicalOperatingConditions; PlateVoltage=130V; GridBias=-8V; AnodeCurrent=22.5mA; AnodeResistance=2050ohm; LoadImpedance=6150ohm

  • Output Power

    65 mW

    TypicalOperatingConditions; PlateVoltage=130V; GridBias=-6V; AnodeCurrent=28.4mA; AnodeResistance=1750ohm; LoadImpedance=1750ohm

  • Total Harmonics Below Fundamental

    31 dB

    TypicalOperatingConditions; PlateVoltage=130V; GridBias=-6V; AnodeCurrent=28.4mA; AnodeResistance=1750ohm; LoadImpedance=1750ohm

  • Output Power

    63 mW

    TypicalOperatingConditions; PlateVoltage=130V; GridBias=-6V; AnodeCurrent=28.4mA; AnodeResistance=1750ohm; LoadImpedance=2900ohm

  • Total Harmonics Below Fundamental

    32.5 dB

    TypicalOperatingConditions; PlateVoltage=130V; GridBias=-6V; AnodeCurrent=28.4mA; AnodeResistance=1750ohm; LoadImpedance=2900ohm

  • Output Power

    56 mW

    TypicalOperatingConditions; PlateVoltage=130V; GridBias=-6V; AnodeCurrent=28.4mA; AnodeResistance=1750ohm; LoadImpedance=5250ohm

  • Total Harmonics Below Fundamental

    38 dB

    TypicalOperatingConditions; PlateVoltage=130V; GridBias=-6V; AnodeCurrent=28.4mA; AnodeResistance=1750ohm; LoadImpedance=5250ohm

  • Output Power

    160 mW

    TypicalOperatingConditions; PlateVoltage=130V; GridBias=-10V; AnodeCurrent=17mA; AnodeResistance=2100ohm; LoadImpedance=2100ohm

  • Total Harmonics Below Fundamental

    24 dB

    TypicalOperatingConditions; PlateVoltage=130V; GridBias=-10V; AnodeCurrent=17mA; AnodeResistance=2100ohm; LoadImpedance=2100ohm

  • Output Power

    125 mW

    TypicalOperatingConditions; PlateVoltage=130V; GridBias=-10V; AnodeCurrent=17mA; AnodeResistance=2100ohm; LoadImpedance=4200ohm

  • Total Harmonics Below Fundamental

    30.4 dB

    TypicalOperatingConditions; PlateVoltage=130V; GridBias=-10V; AnodeCurrent=17mA; AnodeResistance=2100ohm; LoadImpedance=4200ohm

  • Output Power

    107 mW

    TypicalOperatingConditions; PlateVoltage=130V; GridBias=-10V; AnodeCurrent=17mA; AnodeResistance=2100ohm; LoadImpedance=6300ohm

  • Total Harmonics Below Fundamental

    33 dB

    TypicalOperatingConditions; PlateVoltage=130V; GridBias=-10V; AnodeCurrent=17mA; AnodeResistance=2100ohm; LoadImpedance=6300ohm

  • Output Power

    250 mW

    TypicalOperatingConditions; PlateVoltage=160V; GridBias=-10V; AnodeCurrent=32.5mA; AnodeResistance=1800ohm; LoadImpedance=1800ohm

  • Total Harmonics Below Fundamental

    28 dB

    TypicalOperatingConditions; PlateVoltage=160V; GridBias=-10V; AnodeCurrent=32.5mA; AnodeResistance=1800ohm; LoadImpedance=1800ohm

  • Output Power

    180 mW

    TypicalOperatingConditions; PlateVoltage=160V; GridBias=-10V; AnodeCurrent=32.5mA; AnodeResistance=1800ohm; LoadImpedance=3600ohm

  • Total Harmonics Below Fundamental

    33.5 dB

    TypicalOperatingConditions; PlateVoltage=160V; GridBias=-10V; AnodeCurrent=32.5mA; AnodeResistance=1800ohm; LoadImpedance=3600ohm

  • Output Power

    158 mW

    TypicalOperatingConditions; PlateVoltage=160V; GridBias=-10V; AnodeCurrent=32.5mA; AnodeResistance=1800ohm; LoadImpedance=5400ohm

  • Total Harmonics Below Fundamental

    35.5 dB

    TypicalOperatingConditions; PlateVoltage=160V; GridBias=-10V; AnodeCurrent=32.5mA; AnodeResistance=1800ohm; LoadImpedance=5400ohm

Data set 02

1946 Standard Telephone and Cables

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristics

  • Heater/filament voltage

    4 V

  • Heater/filament current

    250 mA

  • Plate resistance

    2000 ohm

  • Transconductance

    0.003 A/V

  • Amplification factor

    6