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Voltage - Triode (with diode, heptode or hexode) ·Diode-Diode-Triode

6FM8

Double-diode high-mu triode for detector, discriminator, control-voltage, and voltage-amplifier service. Paired diodes provide complementary rectification while the triode supplies substantial subsequent gain.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
3
Base
-
Socket code
B9A
Base pins
9
Nominal heater
6.3 V / 450 mA

Description

Duplex-diode high-mu triode with separate cathodes, intended for FM detector and AF voltage-amplifier service.

Socket description

Small-button Noval 9-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
B9A
Base pins
9
Nominal heater voltage
6.3 V
Nominal heater current
450 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

3 physical sections, each with unique specifications.

Section 1

Diode

X-ray radiationInterelectrode capacitances
Max cathode current
5 mA

Diode section 1; maximum continuous current 5 mA.

Section 2

Diode

X-ray radiationInterelectrode capacitances
Max cathode current
5 mA

Diode section 2; maximum continuous current 5 mA.

Section 3

Triode

X-ray radiationInterelectrode capacitances
Plate resistance
58000 Ω
Transconductance
0.0012 S
Amplification factor
70
Max plate voltage
330 V
Max plate dissipation
1.1 W
Max cathode current
5 mA

Triode section.

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

1966 Tung Sol Electronic Tubes 2 of 4

Published operating points and test conditions from this source.

SECTION 1

Diode

Capacitance

  • Diode #1 input capacitance

    2.4 pF

  • Diode #1 cathode-to-all capacitance

    4.6 pF

Other

  • Average diode current

    20 mA

    EachDiode;5VDC

SECTION 2

Diode

Capacitance

  • Diode #2 input capacitance

    2.2 pF

  • Diode #2 cathode-to-all capacitance

    4.8 pF

Other

  • Average diode current

    20 mA

    EachDiode;5VDC

SECTION 3

Triode

Capacitance

  • Triode grid-to-plate capacitance

    1.8 pF

  • Triode input capacitance

    1.5 pF

  • Triode output capacitance

    0.16 pF

Other

  • Plate voltage

    250 V

    ClassA

  • Grid voltage

    -3 V

    ClassA

  • Plate current

    1 mA

    ClassA

Data set 02

1968 General Electric Co

Published operating points and test conditions from this source.

SECTION 1

Diode

Characteristic

  • Average Diode Current

    20 mA

    5V DC Applied

Other

  • Continuous Diode Current

    5 mA

    EachDiode

SECTION 2

Diode

Characteristic

  • Average Diode Current

    20 mA

    5V DC Applied

Other

  • Continuous Diode Current

    5 mA

    EachDiode

SECTION 3

Triode

Characteristic

  • Plate Voltage

    250 V

    TriodeSection ClassA

  • Grid Voltage

    -3 V

    TriodeSection ClassA

  • Plate Current

    1 mA

    TriodeSection ClassA

Data set 03

1971 RCA HB3 Binder 4 of 7

Published operating points and test conditions from this source.

SECTION 1

Diode

Characteristics

  • Voltage (AC or DC) — published value 1

    6 V

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Voltage (AC or DC) — published value 2

    3 V

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Voltage (AC or DC) — published value 3

    10 V

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Current at 6.3 volts — published value 1

    6.3 V

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Current at 6.3 volts — published value 2

    0.45 V

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Grid to plate

    18

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Grid to cathode and heater — published value 1

    1

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Grid to cathode and heater — published value 2

    5

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Plate to cathode and heater

    0.16

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Diode-No.1 plate to triode grid

    0.05

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Diode-No.2 plate to #riode grid

    0.04

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Diode-No.l plate to cathode and heater. 2.4

    2.4

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Diode-No.2 plate to cathode and heater. 2.2

    2.2

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Plate Voltage

    250 V

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Grid Voltage

    -3 V

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Plate Resistance (Approx )

    58000 ohm

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Transconductance

    1200

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Plate Current

    1 mA

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Pin 1-Diode-No.2 — published value 1

    1

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Pin 1-Diode-No.2 — published value 2

    5

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Cathode

    6

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Pin 2-Diode-No.l

    2

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Plate

    7

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Pin 3-Diode-No.l

    3

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Cathode

    8

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Pin 4-Heater — published value 1

    4

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Pin 4-Heater — published value 2

    9

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Plate Current for plate volts = 5 — published value 1

    5 V

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Plate Current for plate volts = 5 — published value 2

    20 V

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

Other

  • PLATE VOLTAGE

    330 V

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Positive-bias value

    0 V

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • PLATE DISSIPATION — published value 1

    1 mA

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • PLATE DISSIPATION — published value 2

    1 mA

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Heater negative with respect to cathode

    200 V

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • Heater positive with respect to cathode

    2006 V

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

  • PLATE CURRENT

    5 mA

    Published datasheet value; multiple numbers on one source row represent separate limits or operating conditions.

SECTION 3

Triode

Other

  • Plate voltage

    250 V

    ClassA

  • Plate current

    1 mA

    ClassA

  • Maximum plate voltage

    330 V

  • Maximum cathode/plate current

    5 mA

Characteristics

  • Plate resistance

    58000 ohm

    ClassA

  • Transconductance

    1200 uS

    ClassA

  • Amplification factor

    70

    ClassA