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Voltage - Triode (single) ·Triode

3A109B

Printed replacement/cross-designation for 3A109A, a repeater triode intended for telephone transmission-amplifier service in communications equipment.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
MEDIUM4BAYONET
Base pins
4
Nominal heater
4 V / 250 mA

Description

3A109B printed cross-designation/replacement designation for 3A109A. Repeater triode, A replacement version.

Socket description

Medium 4-contact bayonet base

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
MEDIUM4BAYONET
Base pins
4
Nominal heater voltage
4 V
Nominal heater current
250 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

Triode

X-ray radiationInterelectrode capacitances
Plate resistance
12000 Ω
Amplification factor
6
Max plate voltage
190 V

Published triode ratings/characteristics promoted from the approved datasheet.

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

1946 Standard Telephone and Cables

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • Grid-anode capacitance

    9 pF

    Direct inter-electrode capacitance

  • Grid-filament capacitance

    6 pF

    Direct inter-electrode capacitance

  • Anode-filament capacitance

    3.6 pF

    Direct inter-electrode capacitance