DF669

Subminiature pentode designed for RF and IF amplifier service, described as similar to type 5678. Its compact construction suits high-frequency small-signal stages in miniature receiving equipment.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: WIRE8
Base pins: 8
Nominal heater: 1.25 V / 50 mA

Description

Subminiature pentode for RF and IF amplifier service, similar to type 5678.

Socket description

Subminiature all-glass 8-wire lead family

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: WIRE8
Base pins: 8
Nominal heater voltage: 1.25 V
Nominal heater current: 50 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: 1000000 Ω
Transconductance: 0.0011 S
Max plate voltage: 90 V
Max screen voltage: 67.5 V
Max plate dissipation: 0.2 W
Max screen dissipation: 0.1 W

Published ratings and characteristics promoted from the printed technical data.

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

HeaterVoltageNominal
1.25 V
Nominal
HeaterCurrentNominal
50 mA
Nominal
Maximum Plate Voltage
90 V
Maximum Screen Voltage
67.5 V
Maximum Plate Dissipation
0.2 W
Maximum Screen Dissipation
0.1 W

Characteristic

Transconductance
1100 µS
Typical
Plate Resistance
1000000 ohm
Typical