Skip to main content
Tube Tinker — Electron Tube Database
Alternatives & variationsDownload PDF datasheet

Voltage Pentode or Tetrode (under 100V) ·Tetrode

EM12

Low-noise electrometer tetrode for digital instruments and precision measuring circuits. High input resistance and reduced noise suit very-small-current measurement.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
P8A
Base pins
8
Nominal heater
6.3 V / 120 mA

Description

Low-noise electrometer tetrode for digital instruments and measuring circuits.

Socket description

European 8-pin side-contact base

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
P8A
Base pins
8
Nominal heater voltage
6.3 V
Nominal heater current
120 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

1 physical section, each with unique specifications.

Section 1

Tetrode

X-ray radiationInterelectrode capacitances
Transconductance
0.00045 S
Amplification factor
40
Max plate voltage
15 V
Max cathode current
0.72 mA

Promoted ratings and characteristics are taken from the printed target-tube entry in the approved PDF.

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

1981 Russian Tubes Katsnelson and Larionov

Published operating points and test conditions from this source.

SECTION 1

Tetrode

Characteristic

  • Heater voltage

    6.3 V

    Published nominal/basic-parameter heater condition.

  • Heater current

    120 mA

    Published heater current.

  • Plate current

    0.35 mA

    Published basic-parameter operating point.

  • Screen current

    0.16 mA

    Published basic-parameter operating point.

  • Transconductance

    450 µS

    Published basic-parameter value; normalized to µS.

  • Amplification factor

    40

    Published amplification factor.

  • Grid current

    0.00000001 mA

    Published in the filename-designated tube entry.

  • Low-frequency equivalent noise resistance

    80 kΩ

    Published in the filename-designated tube entry.

  • Service life

    2000 h

    Published in the filename-designated tube entry.

Other

  • Maximum plate voltage

    15 V

    Published limiting operating value.

  • Maximum cathode current

    0.7200000000000001 mA

    Published limiting cathode-current value.