8524

Sharp-cutoff micro-metal miniature dual-control pentode for Class A amplification and mixer service. Its third grid functions as a second control electrode for frequency conversion and signal-control applications.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: B8D
Base pins: 8
Nominal heater: 6.3 V / 150 mA

Description

Sharp-cutoff micro-metal miniature pentode usable as a class-A amplifier and as a mixer with the third grid as a second control electrode.

Socket description

Subminiature 8-lead

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: B8D
Base pins: 8
Nominal heater voltage: 6.3 V
Nominal heater current: 150 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

Plate resistance: 110000 Ω
Transconductance: 0.0032 S
Max plate voltage: 165 V

Promoted fields are used only where the published value maps cleanly to the locked schema; device-specific microwave, pulse, photoelectric, camera, and indicator data are preserved as parameter rows.

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

1964 RMA EIA

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

Plate voltage
100 V
ClassA;Grid3AtCathode
Screen-grid voltage
100 V
ClassA
Cathode resistor
150 Ohm
ClassA
Plate current
5.3 mA
ClassA;Grid3AtCathode
Screen-grid current
3.6 mA
ClassA;Grid3AtCathode
Conversion transconductance
1280 uS
Mixer
Plate resistance
320000 Ohm
Mixer
Plate current
3.5 mA
Mixer

Characteristics

Plate resistance
110000 Ohm
ClassA;Grid3AtCathode
Transconductance grid1-to-plate
3200 uS
ClassA;Grid3AtCathode
Transconductance grid3-to-plate
500 uS
ClassA;Grid3AtCathode
Plate resistance
50000 Ohm
ClassA;Grid3=-1V
Transconductance grid1-to-plate
1950 uS
ClassA;Grid3=-1V
Transconductance grid3-to-plate
950 uS
ClassA;Grid3=-1V