Skip to main content
Tube Tinker — Electron Tube Database
Alternatives & variationsDownload PDF datasheet

Voltage Radio Detector Converter ·Diode-Pentode

DAF40

Directly heated battery diode-pentode for RF or IF amplification together with signal detection. Its exceptionally economical 1.4 V, 25 mA filament and high-resistance pentode make it particularly suitable for portable receivers.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
2
Base
-
Socket code
-
Base pins
-
Nominal heater
1.4 V / 25 mA

Description

Directly heated diode-pentode for RF or IF amplification in battery receivers.

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
1.4 V
Nominal heater current
25 mA
Parallel heater voltage
1.4 V
Parallel heater current
25 mA
Series capable
Yes

Terminal pinout

Electrical assignments shared by every tube using this base designation.

No verified pinout is recorded for this base designation.

Section ratings

2 physical sections, each with unique specifications.

Section 1

Pentode

X-ray radiationInterelectrode capacitances
Plate resistance
2200000 Ω
Transconductance
0.0007 S
Max plate voltage
135 V
Max screen voltage
85 V
Max plate dissipation
0.2 W
Max screen dissipation
0.02 W

Promoted from clearly identified published ratings/characteristics; additional operating points, capacitances, rectifier conditions, and application-specific values are retained in TUBE_SECTION_PARAMETER.

Section 2

Diode

X-ray radiationInterelectrode capacitances
Rectifier peak inverse voltage
100 V
Rectifier nominal output current
200 mA

Promoted from clearly identified published ratings/characteristics; additional operating points, capacitances, rectifier conditions, and application-specific values are retained in TUBE_SECTION_PARAMETER.

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

1963 Philips Electron Tubes Handbook V1

Published operating points and test conditions from this source.

SECTION 1

Pentode

Capacitance

  • Grid capacitance

    2.8 pF

    Section1

  • Plate capacitance

    3.7 pF

    Section1

  • Grid-to-plate capacitance maximum

    0.0065 pF

    Section1

  • Diode capacitance

    2.1 pF

    Section1

Other

  • Plate voltage

    67.5 V

    RFIFAmplifier

  • Screen voltage

    67.5 V

    RFIFAmplifier

  • Plate current

    0.85 mA

    RFIFAmplifier

  • Screen current

    0.2 mA

    RFIFAmplifier

  • Plate voltage

    90 V

    RFIFAmplifier

Characteristic

  • Transconductance

    700 µS

    Section1

  • Plate resistance

    1.6 MΩ

    67.5VPlate

  • Plate resistance

    2.2 MΩ

    90VPlate

SECTION 2

Diode

Other

  • Peak inverse voltage maximum

    100 V

    DetectorDiode

  • Average diode current maximum

    0.2 mA

    DetectorDiode

  • Peak diode current maximum

    1.2 mA

    DetectorDiode

Data set 02

1999 Philips 0-D

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristic

  • Internal resistance

    1.7 MΩ

    Va=67.5V

Other

  • Maximum anode voltage

    135 V

  • Maximum screen voltage

    85 V