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

6T8A

Triple-diode high-mu triode combining radio detector, discriminator, delayed-AVC, and audio-amplifier functions. Three diode sections support multiple rectification duties while the triode supplies subsequent voltage gain.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 4
Base: -
Socket code: B9A
Base pins: 9
Nominal heater: 6.3 V / 450 mA

Description

6T8A is a DiodesTriode vacuum tube documented in the RCA Receiving Tube Manual. The supplied excerpt was reviewed for heater data, section arrangement, maximum ratings, electrical characteristics, interelectrode capacitances, typical operating conditions, and stated applications.

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

4 physical sections, each with unique specifications.

Section 1

Diode

X-ray radiationInterelectrode capacitances

No fixed ratings are recorded for this section.

Representative row for three high-perveance diode sections.

Section 2

Triode

X-ray radiationInterelectrode capacitances

Plate resistance: 58000 Ω
Transconductance: 0.0012 S
Amplification factor: 70
Max plate voltage: 300 V
Max plate dissipation: 1 W

Triode characteristics use the published 250 V operating point.

Section 3

Diode

X-ray radiationInterelectrode capacitances

No fixed ratings are recorded for this section.

Physical diode section added during approved section-structure reconciliation.

Section 4

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

1968 General Electric Co

Published operating points and test conditions from this source.

SECTION 1

Diode

Other

Continuous Diode Current
5 mA
EachDiode

Capacitance

Diode Input Capacitance
3.8 pF
Section1
Diode Input Capacitance
4.5 pF
Section2
Diode Input Capacitance
3.8 pF
Section3

SECTION 2

Triode

Capacitance

Grid-to-Plate Capacitance
1.8 pF
Input Capacitance
1.6 pF
Output Capacitance
1.1 pF

Other

Plate Voltage
250 V
ClassA
Grid Voltage
-3 V
ClassA
Heater Warm-up Time
11 s
Heater-Cathode Voltage
100 V
ControlledWarmup

Characteristic

Plate Current
1 mA
ClassA