4251A

Directly heated or receiving triode documented by the manufacturer; available source material does not establish a narrower functional category strongly enough for reassignment.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: -
Base pins: -
Nominal heater: 10 V / 16 A

Description

The 4251A is a triode described in the Standard Valves datasheet, using a directly heated filament cathode and published operating data.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: -
Base pins: -
Nominal heater voltage: 10 V
Nominal heater current: 16 A
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: 2750 Ω
Transconductance: 0.0038 S
Amplification factor: 10.5
Max plate voltage: 3000 V
Max plate dissipation: 1000 W
Max grid dissipation: 50 W
Max cathode current: 600 mA

Published ratings and characteristics promoted where directly established by the 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

1937 Standard Valves

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristics

Total emission
6 A
Published datasheet value
Grid-anode capacitance
8 pF
Published datasheet value
Anode-filament capacitance
6 pF
Published datasheet value
Grid-filament capacitance
10 pF
Published datasheet value

Other

Maximum frequency for above ratings
30 MHz
Published datasheet value

Data set 02

1946 Standard Telephone and Cables

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristics

Mutual conductance
3800 µS
Published characteristic; normalized from mA/V

Other

Grid-anode capacity
8 pF
Published interelectrode capacitance
Anode-filament capacity
6 pF
Published interelectrode capacitance
Maximum direct anode current
600 mA
Maximum safe operating rating