Tuning Indicator ·TuningIndicator
Directly heated OSRAM fluorescent visual tuning indicator for receiver tuning, providing a visible response to changing control conditions.
GU1: OSRAM visual tuning indicator. The complete approved OSRAM sheet was read for construction, characteristics, operating data, and application guidance.
European 4-pin base
General specifications
Properties common to every published source and operating point.
Electrical assignments shared by every tube using this base designation.
No verified pinout is recorded for this base designation.
1 physical section, each with unique specifications.
Section 1
Published characteristics/ratings were promoted when unambiguous; remaining operating values are preserved in TUBE_SECTION_PARAMETER.
Source-dependent data
Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.
Data set 01
Published operating points and test conditions from this source.
Maximum rectified current
250 mA
Half-wave mercury rectifier
Rated supply voltage
1000 V
Source describes delivery up to 250 mA at 1,000 V
Data set 02
Published operating points and test conditions from this source.
Heater/filament voltage
4 V
Heater/filament current
3 A
Display function
Visual tuning indication
Maximum anode voltage
0 V