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Voltage Radio Detector Converter ·Pentode-Triode

5BR8

Medium-mu triode plus sharp-cutoff pentode used as a combined oscillator and mixer in VHF television tuners.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
2
Base
9FA
Socket code
B9A
Base pins
9
Nominal heater
4.7 V / 600 mA

Description

Reference/equivalence entry for a medium-mu triode plus sharp-cutoff pentode used as a combined oscillator and mixer in VHF television tuners.

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
9FA
Socket code
B9A
Base pins
9
Nominal heater voltage
4.7 V
Nominal heater current
600 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

9FA - Terminal pinout

Electrical assignments shared by every tube using this base designation.

TerminalSectionConnectionEvidence
PIN1Base PinBG1 — Control Grid

Original chart label: 2G1; manufacturer verification pending

Unverified

EIA Base Connections, printed page 132, 9FA

PIN2Base PinBP — Plate (Anode)

Original chart label: 2P; manufacturer verification pending

Unverified

EIA Base Connections, printed page 132, 9FA

PIN3Base PinBK — Cathode

Original chart label: 2K; manufacturer verification pending

Unverified

EIA Base Connections, printed page 132, 9FA

PIN4Base Pin—H — Heater

Original chart label: H; manufacturer verification pending

Unverified

EIA Base Connections, printed page 132, 9FA

PIN5Base Pin—H — Heater

Original chart label: H; manufacturer verification pending

Unverified

EIA Base Connections, printed page 132, 9FA

PIN6Base PinAP — Plate (Anode)

Original chart label: 1P; manufacturer verification pending

Unverified

EIA Base Connections, printed page 132, 9FA

PIN7Base PinAG2 — Screen Grid

Original chart label: 1G2; manufacturer verification pending

Unverified

EIA Base Connections, printed page 132, 9FA

PIN8Base PinAG3 — Suppressor GridGroup 9FA8

Original chart label: 1G3; manufacturer verification pending

Unverified

EIA Base Connections, printed page 132, 9FA

PIN8Base PinAK — CathodeGroup 9FA8

Original chart label: 1K; manufacturer verification pending

Unverified

EIA Base Connections, printed page 132, 9FA

PIN8Base Pin—IS — Internal ScreenGroup 9FA8

Original chart label: IS; manufacturer verification pending

Unverified

EIA Base Connections, printed page 132, 9FA

Section ratings

2 physical sections, each with unique specifications.

Section 1

Triode

X-ray radiationInterelectrode capacitances
Plate resistance
5000 Ω
Transconductance
0.0085 S
Amplification factor
40
Max plate voltage
300 V
Max plate dissipation
2.7 W
Rectifier max heater-cathode voltage
200 V
Rectifier warm-up time
11 s

Referenced ratings not printed in this source; not inferred.

Section 2

Pentode

X-ray radiationInterelectrode capacitances
Plate resistance
400000 Ω
Transconductance
0.0052 S
Max plate voltage
300 V
Max screen voltage
300 V
Max plate dissipation
2.8 W
Max screen dissipation
0.5 W
Rectifier max heater-cathode voltage
200 V
Rectifier warm-up time
11 s

Referenced ratings not printed in this source; not inferred.

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 1 of 4

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

  • Heater/filament voltage

    4.7 V

    Published rating

  • Heater/filament current

    600 mA

    Published rating

  • Triode transconductance

    8500 µS

    TriodeSection

  • Triode amplification factor

    40

    TriodeSection

  • Pentode transconductance

    5200 µS

    PentodeSection

Capacitance

  • Pentode grid-to-plate capacitance

    0.008 pF

    WithShield

  • Pentode input capacitance

    5 pF

    Published

Other

  • Application

    Local oscillator and pentode mixer

    VHF

  • Triode plate voltage

    150 V

    TriodeSection

  • Triode plate current

    15 mA

    TriodeSection

  • Pentode plate voltage

    250 V

    PentodeSection

  • Pentode screen voltage

    110 V

    PentodeSection

  • Pentode plate current

    10 mA

    PentodeSection

  • Pentode screen current

    3.5 mA

    PentodeSection

Data set 02

1968 General Electric Co

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

  • Heater Warmup Time

    11 s

Data set 03

1971 RCA HB3 Binder 4 of 7

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • Plate voltage

    150 V

    Triode;ClassA

  • Cathode bias resistor

    56 ohm

    Triode;ClassA

  • Plate current

    18 mA

    Triode;ClassA

  • Heater/filament voltage

    4.7 V

    DerivativeSheet

  • Heater/filament current

    600 mA

    DerivativeSheet

  • Heater warm-up time

    11 s

    ControlledWarmup

Characteristic

  • Plate resistance

    5000 ohm

    Triode

  • Transconductance

    8500 uS

    Triode

  • Amplification factor

    40

    Triode

Capacitance

  • Grid-to-plate capacitance

    1.8 pF

    Triode

SECTION 2

Pentode

Other

  • Plate voltage

    250 V

    Pentode;ClassA

  • Screen voltage

    110 V

    Pentode;ClassA

  • Cathode bias resistor

    68 ohm

    Pentode;ClassA

  • Plate current

    10 mA

    Pentode;ClassA

  • Screen current

    3.5 mA

    Pentode;ClassA

Characteristic

  • Plate resistance

    400000 ohm

    Pentode

  • Transconductance

    5200 uS

    Pentode

Capacitance

  • Grid-to-plate capacitance

    0.008 pF

    Pentode;Shielded

  • Input capacitance

    5 pF

    Pentode

  • Output capacitance

    3.5 pF

    Pentode