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Voltage - Triode (single) ·Triode

4205E

Directly heated Standard Valves triode with oxide-coated filament; related versions use specially treated grid and anode surfaces to reduce secondary emission.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
UX4
Base pins
4
Nominal heater
4.5 V / 600 mA

Description

Directly heated triode. M.4205-E valve is similar to 4205-E but has the grid and anode specially treated to reduce secondary emission. SPECIFICATION. Cathode. Oxide coated filament. Constant current type. Base. Medium 4-pin

Socket description

Medium-shell UX 4-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
UX4
Base pins
4
Nominal heater voltage
4.5 V
Nominal heater current
600 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
3500 Ω
Transconductance
0.002 S
Amplification factor
7
Max plate voltage
400 V
Max plate dissipation
15 W
Max cathode current
50 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

  • Anode-grid capacitance

    4.8 pF

  • Anode-filament capacitance

    3.3 pF

  • Grid-filament capacitance

    5.2 pF

Other

  • Maximum direct anode current

    50 mA

  • Maximum direct grid current

    10 mA

  • Maximum frequency for full ratings

    15 MHz

  • Anode voltage at 30 MHz

    300 V

    30MHz

Data set 02

1946 Standard Telephone and Cables

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristics

  • Mutual conductance

    2000 µS

    Published characteristic; normalized from mA/V

Other

  • Maximum direct anode current

    50 mA

    Maximum safe operating rating