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Power - Pentode Single (NOT beam) (under 10W) ·Pentode

N108

Marconi miniature output pentode with an economical 4 V, 100 mA heater for audio power service.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
B7G
Base pins
7
Nominal heater
4 V / 100 mA

Description

The Marconi N108 is a miniature output pentode with 0.1 a heater for audio-output service.

Socket description

Miniature 7-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
B7G
Base pins
7
Nominal heater voltage
4 V
Nominal heater current
100 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

Pentode

X-ray radiationInterelectrode capacitances
Plate resistance
23200 Ω
Transconductance
0.0095 S
Max plate voltage
165 V
Max screen voltage
165 V
Max plate dissipation
9 W
Max screen dissipation
3 W

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

1955 Marconi

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Heater voltage

    4 V

  • Heater current

    100 mA

  • Maximum plate voltage

    165 V

  • Maximum screen voltage

    165 V

  • Maximum plate dissipation

    9 W

  • Maximum screen dissipation

    3 W

Characteristic

  • Transconductance

    9500 uS

  • Plate resistance

    23200 ohm

Application

  • Primary application

    Miniature output pentode with 0.1 A heater for audio-output service.