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

Tuning Indicator ·TuningIndicator

8569

Long-life directly heated end-view indicator triode producing blue-green light proportional to plate current for compact visual electrical-level indication.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
-
Base pins
4
Nominal heater
0.7 V / 35 mA

Description

Long-life filamentary high-vacuum end-view indicator triode producing blue-green light proportional to plate current.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
-
Base pins
4
Nominal heater voltage
0.7 V
Nominal heater current
35 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

Tuning Indicator

X-ray radiationInterelectrode capacitances
Amplification factor
22
Max plate voltage
65 V
Max cathode current
0.75 mA

Filamentary indicator triode; optical light-output characteristics retained as parameters.

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

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Tuning Indicator

Other

  • Heater voltage

    0.7 V

    Nominal

  • Heater current

    35 mA

    Nominal

  • Plate voltage

    50 V

    Published operating table; OperatingPoint1

  • Plate voltage

    50 V

    Published operating table; OperatingPoint1

Data set 02

1966 Tung Sol Electronic Tubes 4 of 4

Published operating points and test conditions from this source.

SECTION 1

Tuning Indicator

Other

  • Filament voltage

    0.7 V

  • Filament current

    35 mA

  • Maximum plate voltage

    65 V

  • Maximum negative grid voltage

    -50 V

  • Maximum plate current

    750 uA

  • Plate voltage

    50 V

    FilamentDCNegativeGrounded

  • Grid voltage

    0 V

    FilamentDCNegativeGrounded

  • Grid resistor

    100 kohm

  • Plate current

    450 uA

    FilamentAC;Grid0V

  • Light output

    5 millicandle

    FilamentAC;Grid0V

  • Plate current

    5 uA

    FilamentAC;Grid=-3V;LessThan

  • Light output

    Not visible

    FilamentAC;Grid=-3V

Characteristic

  • Plate current

    380 uA

    FilamentDCNegativeGrounded

  • Amplification factor

    22

Capacitance

  • Grid-to-plate capacitance

    1.9 pF

  • Input capacitance

    1.6 pF

  • Output capacitance

    1.7 pF