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Tube Tinker — Electron Tube Database
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Tuning Indicator ·TuningIndicator

1M1

Directly heated subminiature low-power tuning indicator for battery-operated or mains-powered radio receivers.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
-
Base pins
-
Nominal heater
1.4 V / 25 mA

Description

Directly heated subminiature tuning indicator for mains-powered or 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
-
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
Max plate voltage
90 V
Max plate dissipation
0.025 W
Max cathode current
0.3 mA

Published ratings and characteristics promoted where clearly stated; identical repeated sections compressed when applicable.

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

1973 Mazda Valves Binder 2

Published operating points and test conditions from this source.

SECTION 1

Tuning Indicator

Characteristics

  • Heater or filament voltage

    1.4 V

    Published nominal value

  • Heater or filament current

    25 mA

    Published nominal value

Other

  • Maximum plate dissipation

    0.025 W

    Published maximum rating

  • Minimum anode voltage

    45 V

    Published minimum operating voltage