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Voltage Pentode - High Frequency (single) ·Pentode

CF7

All-current high-frequency pentode for RF, IF, and audio-frequency voltage amplification, closely related to the AF7.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
P8A
Base pins
8
Nominal heater
13 V / 200 mA

Description

All-current high-frequency pentode, explicitly cross-referenced to AF7 for RF, IF, and audio amplifier use.

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
13 V
Nominal heater current
200 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
2000000 Ω
Transconductance
0.0021 S
Max plate voltage
250 V
Max screen voltage
125 V
Max plate dissipation
1 W
Max screen dissipation
0.3 W
Max cathode current
6 mA

Straight-characteristic RF pentode; promoted values from published nominal operating point.

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

1938 Philips Miniwatt Vacuum Tube Catalog

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Plate voltage

    200 V

    Published table operating point

  • Plate current

    3 mA

    Published table operating point

  • Control-grid bias

    2 V

    Published table operating point

  • Screen voltage

    100 V

    Published table operating point

  • Screen current

    1.1 mA

    Published table operating point

Characteristic

  • Transconductance

    2100000 µS

    Published table characteristic

  • Plate resistance

    700000 ohm

    Published table characteristic

  • Heater/filament voltage

    13 V

    Published heater/filament rating

  • Heater/filament current

    200 mA

    Published heater/filament rating

Capacitance

  • Grid-to-plate capacitance

    0.003 pF

    Published table capacitance

Data set 02

1953 RFT Rundfunk Technik

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Anode voltage

    200 V

  • Screen-grid voltage

    100 V

  • Cathode resistance

    500 Ω

  • Transconductance

    2.1 mA/V

  • Plate resistance

    2 MΩ

  • Resistance-amplifier supply voltage

    200 V

  • Voltage gain

    135

  • Cold anode voltage maximum

    550 V

  • Cold screen-grid voltage maximum

    400 V

Capacitance

  • Input capacitance

    6.6 pF

  • Output capacitance

    7.6 pF

Data set 03

195X Tunsgram

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Typical plate voltage

    200 V

  • Typical screen voltage

    100 V

  • Typical plate current

    3 mA

  • Maximum no-current anode voltage

    550 V

  • Maximum heater-cathode voltage

    125 V

Characteristic

  • Maximum transconductance

    0.0024 A/V

Data set 04

1999 Philips 0-D

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Typical plate current

    3 mA

Characteristic

  • Maximum transconductance

    2400 µS