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Tube Tinker — Electron Tube Database
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Tuning Indicator ·Triode-TuningIndicator

AM1

Four-volt tuning-cross visual indicator producing a fluorescent cross-pattern controlled by signal-derived voltage for accurate receiver tuning.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
2
Base
P26
Socket code
-
Base pins
-
Nominal heater
4 V / 300 mA

Description

4 V tuning-cross visual indicator. Electrical ratings and operating characteristics were extracted from the supplied 4-volt valve data table, including the published heater data and available section-level values.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
P26
Socket code
-
Base pins
-
Nominal heater voltage
4 V
Nominal heater current
300 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

P26 - 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

Tuning Indicator

X-ray radiationInterelectrode capacitances
Max plate voltage
250 V

Visual tuning-cross indicator.

Section 2

Triode

X-ray radiationInterelectrode capacitances

No fixed ratings are recorded for this section.

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

1938 Philips Miniwatt Vacuum Tube Catalog

Published operating points and test conditions from this source.

SECTION 1

Tuning Indicator

Other

  • Anode voltage

    250 V

  • Anode current

    0.095 mA

  • Maximum indicated current

    0.021 mA

Characteristics

  • Grid control voltage

    -54 V

  • Sensitivity

    9.5