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25HP4

Twenty-five-inch direct-view monochrome television picture tube with electrostatic focusing, magnetic deflection, and a high-voltage P4 display system for large-screen receiver service.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized

Sections: 1
Base: -
Socket code: B8H
Base pins: -
Nominal heater: 6.3 V / 450 mA

Description

25-inch 110-degree monochrome television CRT with electrostatic focus, magnetic deflection, and aluminized P4 screen.

Socket description

Neoeightar 8-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: B8H
Base pins: -
Nominal heater voltage: 6.3 V
Nominal heater current: 450 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

Cathode Ray

X-ray radiationInterelectrode capacitances

Max plate voltage: 23000 V

Published source ratings and characteristics promoted where applicable; additional electrical and operating data 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

1964 RMA EIA

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Application

Application
Cathode-ray display / television / instrumentation

Characteristics

Focusing method
Electrostatic
Deflection method
Magnetic
Diagonal deflection angle
110 deg
Horizontal deflection angle
89 deg
Vertical deflection angle
82 deg
Heater warm-up time
11 s

Capacitance

Cathode-to-all capacitance
5 pF
Grid1-to-all capacitance
6 pF
External coating capacitance minimum
2000 pF
External coating capacitance maximum
2500 pF

Other

Anode voltage minimum
12000 V
Anode voltage maximum
23000 V
Focus-electrode positive voltage maximum
1000 V
Focus-electrode negative voltage minimum
-500 V
Grid2 voltage minimum
25 V
Grid2 voltage maximum
60 V
Heater voltage minimum
5.8 V
Heater voltage maximum
6.9 V
Typical anode voltage
16000 V
Typical focus voltage
250 V
Typical grid2 voltage
50 V
Cathode cutoff voltage range
35 to 55 V
Grid1 circuit resistance maximum
1.5 Mohm