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Voltage Pentode - Sharp Cutoff (single) ·Pentode

C3B

European receiving pentode for small-signal voltage amplification, combining useful transconductance with high plate resistance.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
P8A
Base pins
8
Nominal heater
4 V / 1.1 A

Description

A 4 V receiving pentode with 150 V screen operation, 3.5 mA/V transconductance and a 2 W maximum anode dissipation.

Socket description

European 8-pin side-contact base

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
P8A
Base pins
8
Nominal heater voltage
4 V
Nominal heater current
1.1 A
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
700000 Ω
Transconductance
0.0035 S
Max plate voltage
250 V
Max screen voltage
150 V
Max plate dissipation
2 W
Max screen dissipation
0.7 W

Published ratings and characteristics promoted from the approved source.

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

1953 RFT Rundfunk Technik

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Anode voltage

    220 V

  • Screen-grid voltage

    150 V

  • Cathode resistance

    175 Ω

  • Anode current

    8 mA

  • Screen-grid current

    2.5 mA

  • Cold anode voltage maximum

    400 V

  • Cold screen-grid voltage maximum

    400 V

  • Grid leak resistance maximum

    400 kΩ

Capacitance

  • Grid-anode capacitance

    6 mpF