12C8GT

GT-envelope double-diode pentode for detector, AVC, and low-frequency voltage-amplifier functions. Two diodes perform detection and control rectification while the pentode supplies subsequent LF gain.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 3
Base: -
Socket code: IO
Base pins: 8
Nominal heater: 12.6 V / 150 mA

Description

The BRIMAR 12C8GT is a double-diode amplifier pentode with a 12.6 V, 0.15 A heater and a pentode section having 0.6 megohm anode impedance.

Socket description

International Octal

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: IO
Base pins: 8
Nominal heater voltage: 12.6 V
Nominal heater current: 150 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: 1 mA

Two similar diode sections; represented once under identical-section compression.

Section 2

Pentode

X-ray radiationInterelectrode capacitances

Plate resistance: 600000 Ω
Transconductance: 0.00112 S
Max plate voltage: 300 V
Max screen voltage: 125 V
Max plate dissipation: 2.25 W
Max screen dissipation: 0.3 W

Published Ferranti ratings and characteristics promoted where applicable; additional operating and application data retained as parameters.

Section 3

Diode

X-ray radiationInterelectrode capacitances

No fixed ratings are recorded for this section.

Second physical detector diode; duplicated from identical diode 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

1948 Brimar Radio Valve Manual

Published operating points and test conditions from this source.

SECTION 2

Pentode

Characteristics

Anode Voltage
250 V
Anode Current
9 mA
Screen Voltage
125 V
Screen Current
2.3 mA
Control Grid Voltage
-3 V
Cathode Bias Resistor
250 ohm

Data set 02

1961 Ferranti Technical Handbook

Published operating points and test conditions from this source.

SECTION 1

Diode

Application

Application
Detector / AVC

SECTION 2

Pentode

Application

Application
LF amplifier