2P5B

Rugged directly heated high-frequency amplifier pentode.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: -
Base pins: -
Nominal heater: 1.2 V / 185 mA

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: 1.2 V
Nominal heater current: 185 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

Transconductance: 0.0033 S

Russian 2P5B high-durability directly heated oxide-coated miniature pentode for high-frequency oscillation and amplification, flexible lead construction. Filament 1.2 V 185 mA (160–210 mA range). Manufacturer-derived summary lists anode 90 V, screen 90 V, grid 1 bias -4.5 V, typical transconductance 3.3 mA/V (range 2.4–4.2 mA/V), anode current 18 mA, stated anode power 2.3 W, reverse grid current 0.1 µA and microphonic noise 130 mV. These voltages and anode-power figures are not explicitly designated absolute maxima and are retained as operating data in notes, not promoted to max fields. Section index standardized from 0 to 1.

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

2026 Russian Receiving

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristic

Plate Voltage
90 V
Typical anode voltage

Other

Heater/filament voltage
1.2 V
Filament voltage
Heater/filament current
185 mA
Filament current