4ZH1L

Russian indirectly heated screened RF pentode for high-frequency voltage and power amplification and oscillation up to approximately 200 MHz. Nominal heater 4.2 V, 225 mA; published transconductance 1.7 mA/V.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: -
Base pins: -
Nominal heater: 4.2 V / 225 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: 4.2 V
Nominal heater current: 225 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: 0.0017 S

Russian 4ZH1L screened, indirectly heated oxide-cathode high-frequency pentode for voltage/power amplification and RF oscillation up to approximately 200 MHz. Heater 4.2 V 225 mA (210–240 mA range); manufacturer-derived summary lists anode 150 V at about 2 mA (1.4–3.3 mA range), screen grid 75 V, control-grid bias -2.1 V, transconductance 1.7 mA/V (range 1.2–2.1 mA/V), and printed anode power 2 W; microphone-noise figure 150 mV. These voltages/power are not explicitly absolute maximum ratings, so maximum plate/screen voltage and dissipation remain NULL. Glass envelope with exterior shielding, reported RSH7 socket.

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
150 V
Screen Voltage
75 V
Grid Voltage
-2.1 V
Plate Current
2 mA