DF11

Telefunken directly heated variable-mu pentode designed for RF and IF amplification in battery receivers. Its filamentary cathode combines low-power portable operation with automatic gain-control capability.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: -
Base pins: -
Nominal heater: 1.2 V / 25 mA

Description

The Telefunken DF11 is a directly heated variable-mu pentode for RF and 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: 1.2 V
Nominal heater current: 25 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: 0.0007 S
Max plate voltage: 150 V
Max screen voltage: 150 V

Variable-mu RF/IF pentode.

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

1959 Telefunken

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristics

Plate Voltage
120 V
Screen Voltage
60 V
Plate Current
1.2 mA
Screen Current
0.22 mA
Transconductance
700 uS
Control Range
100 ratio
RF/IF amplifier