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Voltage - Triode (single) ·Triode

7A4

General-purpose triode for amplification or electronic service as documented by the manufacturer.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
5AC
Socket code
LOCTAL8
Base pins
8
Nominal heater
6.3 V / 300 mA

Description

A medium-mu Lock-In triode designed for general amplifier service with Class A operating characteristics.

Socket description

Loctal 8-contact base

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
5AC
Socket code
LOCTAL8
Base pins
8
Nominal heater voltage
6.3 V
Nominal heater current
300 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

5AC - 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

Triode

X-ray radiationInterelectrode capacitances
Plate resistance
6000 Ω
Transconductance
0.0065 S
Amplification factor
20
Max plate voltage
300 V
Max plate dissipation
2.5 W
Max cathode current
20 mA

Published handbook ratings and representative operating characteristics reviewed.

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

195X General Electric Essential Characteristics

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • Maximum plate voltage

    300 V

    Published handbook rating

  • Plate voltage

    250 V

    ClassA

  • Control-grid bias

    8 V

    ClassA

  • Plate current

    9 mA

    ClassA

Characteristic

  • Plate resistance

    7700 ohm

    Published handbook characteristic

  • Transconductance

    2600 µS

    Published handbook characteristic

  • Amplification factor

    20

    Published handbook characteristic

  • Heater voltage

    6.3 V

    Published heater rating

  • Heater current

    300 mA

    Published heater rating

Data set 02

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • Heater voltage

    6.3 V

    Nominal

  • Heater current

    300 mA

    Nominal

  • Plate voltage

    300 V

    Typical operating conditions

  • Plate current

    109 mA

    Typical operating conditions