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Voltage Pentode or Tetrode (under 100V) ·Pentode

512AX

Extremely low-power directly heated subminiature pentode for audio and direct-coupled voltage amplification in hearing aids and portable instruments.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
512AX
Socket code
-
Base pins
-
Nominal heater
0.625 V / 20 mA

Description

Directly heated subminiature voltage-amplifier pentode for resistance-coupled audio and direct-coupled amplifiers, including hearing aids and portable instruments.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
512AX
Socket code
-
Base pins
-
Nominal heater voltage
0.625 V
Nominal heater current
20 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

512AX - 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
1250000 Ω
Transconductance
0.00016 S
Max plate voltage
45 V
Max screen voltage
45 V

Published maximum ratings, operating characteristics, rectifier/deflection data 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

1938 Raytheon

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristics

  • Heater or filament voltage

    0.625 V

    Published nominal value

  • Heater or filament current

    20 mA

    Published nominal value

  • Transconductance

    160 µS

    Published characteristic

Data set 02

195X General Electric Essential Characteristics

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Maximum plate voltage

    45 V

    Published handbook rating

  • Maximum screen voltage

    45 V

    Published handbook rating

  • Plate voltage

    22.5 V

    ClassA

  • Screen voltage

    22.5 V

    ClassA

  • Control-grid bias

    3.625 V

    ClassA

  • Plate current

    0.125 mA

    ClassA

  • Load resistance

    3000 ohm

    ClassA

  • Power output

    0.03 W

    ClassA

Characteristic

  • Plate resistance

    1250000 ohm

    Published handbook characteristic

  • Transconductance

    160 µS

    Published handbook characteristic

  • Heater/filament voltage

    0.625 V

    Published heater/filament rating

  • Heater/filament current

    20 mA

    Published heater/filament rating