1P5B

Russian high-durability miniature pentode for HF oscillation and amplification. Uses a directly heated oxide-coated filament rated 1.2 V, 120 mA, and flexible leads.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: -
Base pins: -
Nominal heater: 1.2 V / 120 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: 120 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: 0.0014 S

Russian 1P5B directly heated high-durability miniature pentode for high-frequency oscillation and amplification, oxide-coated 1.2 V 120 mA filament (manufacturer current range 100–140 mA), flexible leads. Listed anode voltage 90 V, screen voltage 90 V, grid 1 bias -4.5 V, transconductance 1.4 mA/V (0.3–2.5 range), stated anode power 1.7 W, reverse grid current 0.1 µA and microphonic noise 130 mV. Summary does not explicitly identify voltage or power entries as maximum ratings, so maximum fields left unpopulated.

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

Other

Plate Voltage
90 V
Screen Voltage
90 V
Grid Voltage
-4.5 V