8447

Series-heater double-diode medium/high-mu triode with unusually strong transconductance for detector and amplifier service. Paired diodes provide complementary rectification while the low-resistance triode supplies substantial current drive.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 3
Base: -
Socket code: B9A
Base pins: 9
Nominal heater: 13.5 V / 190 mA

Description

Reliable mobile-radio double high-perveance diode and high-mu triode combination with separate cathodes.

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: 13.5 V
Nominal heater current: 190 mA
Parallel heater voltage: 6.75 V
Parallel heater current: 380 mA
Series capable: Yes

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

Rectifier peak inverse voltage: 300 V
Rectifier peak forward current: 60 mA

Section 2

Triode

X-ray radiationInterelectrode capacitances

Plate resistance: 10900 Ω
Transconductance: 0.0055 S
Amplification factor: 60
Max plate voltage: 300 V
Max plate dissipation: 2.5 W

Section 3

Diode

X-ray radiationInterelectrode capacitances

No fixed ratings are recorded for this section.

Physical diode section added during approved section-structure reconciliation.

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

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Diode

Other

Heater voltage
13.5 V
Nominal
Heater current
190 mA
Nominal
Plate voltage
250 V
Published operating table; OperatingPoint1

Characteristic

Plate current
10 mA
Published operating table; OperatingPoint1
Transconductance
5500 uS
Published operating table; OperatingPoint1

SECTION 2

Triode

Other

Heater voltage
13.5 V
Nominal
Heater current
190 mA
Nominal
Plate voltage
250 V
Published operating table; OperatingPoint1

Characteristic

Plate current
10 mA
Published operating table; OperatingPoint1
Transconductance
5500 uS
Published operating table; OperatingPoint1