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3A105B

Low-noise Standard Valves triode designed for sensitive small-signal amplification where reduced internally generated noise is important.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: B4
Base pins: 4
Nominal heater: 13 V / 190 mA

Description

3A105B is a low noise triode described in the Standard Valves datasheet. The source provides construction, electrical constants, limiting conditions, and operating information.

Socket description

European 4-pin base

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: B4
Base pins: 4
Nominal heater voltage: 13 V
Nominal heater current: 190 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: 19000 Ω
Transconductance: 0.0021 S
Amplification factor: 40
Max plate voltage: 250 V
Max plate dissipation: 2.5 W
Max cathode current: 15 mA

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
1.5 pF
Direct inter-electrode capacitance
Grid-cathode capacitance
2.4 pF
Direct inter-electrode capacitance
Anode-cathode capacitance
4.5 pF
Direct inter-electrode capacitance