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Voltage Pentode or Tetrode (under 100V) ·Pentode

1T4

Directly heated variable-mu pentode designed for RF and IF amplifier service in battery receivers. Its low-power filament and gain-control characteristic make it a widely applicable portable-receiver signal tube.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: 8AR
Socket code: B7G
Base pins: 7
Nominal heater: 1.4 V / 50 mA

Description

Directly heated variable-mu pentode for RF and IF amplifier service in battery receivers.

Socket description

Miniature 7-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: 8AR
Socket code: B7G
Base pins: 7
Nominal heater voltage: 1.4 V
Nominal heater current: 50 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

8AR - 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

Pentode

X-ray radiationInterelectrode capacitances

Plate resistance: 500000 Ω
Transconductance: 0.0009 S
Max plate voltage: 90 V
Max screen voltage: 90 V
Max cathode current: 5.5 mA

Remote-cutoff RF pentode for variable-gain battery receiver RF and IF stages.

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

1948 Brimar Radio Valve Manual

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristic

HeaterOrFilamentVoltage
1.4 V
HeaterOrFilamentCurrent
50 mA
Transconductance
900 uS
PlateVoltage=90V;ScreenVoltage=67.5V

Data set 02

1958 Brimar Radio Valve No 7

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

Plate Voltage
90 V
Plate Current
3.5 mA
Screen Voltage
67.5 V
Screen Current
1.4 mA

Characteristic

Transconductance
900 µS
Plate Resistance
500000 ohm

Data set 03

195X General Electric Essential Characteristics

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

Plate voltage
90 V
ClassA; OperatingPoint1
Screen voltage
67.5 V
ClassA; OperatingPoint1
Control-grid bias
0 V
ClassA; OperatingPoint1
Plate current
3.5 mA
ClassA; OperatingPoint1
Screen current
1.4 mA
ClassA; OperatingPoint1
Plate voltage
90 V
ClassA; OperatingPoint2
Screen voltage
45 V
ClassA; OperatingPoint2
Control-grid bias
0 V
ClassA; OperatingPoint2
Plate current
1.8 mA
ClassA; OperatingPoint2
Screen current
0.67 mA
ClassA; OperatingPoint2
Plate voltage
67.5 V
ClassA; OperatingPoint3
Screen voltage
67.5 V
ClassA; OperatingPoint3
Control-grid bias
0 V
ClassA; OperatingPoint3
Plate current
3.4 mA
ClassA; OperatingPoint3
Screen current
1.5 mA
ClassA; OperatingPoint3
Plate voltage
45 V
ClassA; OperatingPoint4
Screen voltage
45 V
ClassA; OperatingPoint4
Control-grid bias
0 V
ClassA; OperatingPoint4
Plate current
1.7 mA
ClassA; OperatingPoint4
Screen current
0.7 mA
ClassA; OperatingPoint4

Data set 04

1961 Ferranti Technical Handbook

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristic

HeaterOrFilamentVoltage
1.4 V
HeaterOrFilamentCurrent
50 mA
CutoffCharacteristic
Variable mu

Data set 05

1966 Tung Sol Electronic Tubes 1 of 4

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

Plate voltage
90 V
RFIFAmplifier
Screen voltage
67.5 V
RFIFAmplifier
Plate current
2.3 mA
RFIFAmplifier
Screen current
0.7 mA
RFIFAmplifier

Characteristic

Transconductance
900 µS
Section1
Plate resistance
1 MΩ
Section1

Data set 06

1968 General Electric Co

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

Plate voltage
45 V
ClassA;OperatingPoint1
Screen voltage
45 V
ClassA;OperatingPoint1
Plate current
1.7 mA
ClassA;OperatingPoint1
Screen current
0.7 mA
ClassA;OperatingPoint1
Plate voltage
67.5 V
ClassA;OperatingPoint2
Screen voltage
67.5 V
ClassA;OperatingPoint2
Plate current
3.4 mA
ClassA;OperatingPoint2
Screen current
1.5 mA
ClassA;OperatingPoint2
Plate voltage
90 V
ClassA;OperatingPoint3
Screen voltage
45 V
ClassA;OperatingPoint3
Plate current
1.8 mA
ClassA;OperatingPoint3
Screen current
0.65 mA
ClassA;OperatingPoint3
Plate voltage
90 V
ClassA;OperatingPoint4
Screen voltage
67.5 V
ClassA;OperatingPoint4
Plate current
3.5 mA
ClassA;OperatingPoint4
Screen current
1.4 mA
ClassA;OperatingPoint4

Characteristic

Plate resistance
350000 ohm
ClassA;OperatingPoint1
Transconductance
700 uS
ClassA;OperatingPoint1
Plate resistance
250000 ohm
ClassA;OperatingPoint2
Transconductance
875 uS
ClassA;OperatingPoint2
Plate resistance
800000 ohm
ClassA;OperatingPoint3
Transconductance
750 uS
ClassA;OperatingPoint3
Plate resistance
500000 ohm
ClassA;OperatingPoint4
Transconductance
900 uS
ClassA;OperatingPoint4

Data set 07

1968 Mazda Belvu

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristics

Heater or filament voltage
1.4 V
Published nominal value
Heater or filament current
50 mA
Published nominal value
Transconductance
875 µS
Published operating characteristic
Transconductance
875 µS
67.5 V operating condition