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25DP4

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: B12A
Base pins: -
Nominal heater: 6.3 V / 300 mA

Description

Twenty-five-inch bonded-frame television CRT with electrostatic focus, 110-degree magnetic deflection, gray-filter faceplate, and aluminized P4 screen.

Socket description

Duodecal 12-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: B12A
Base pins: -
Nominal heater voltage: 6.3 V
Nominal heater current: 300 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: 22000 V
Max screen voltage: 700 V

Direct-view CRT; source includes X-radiation exposure warning at elevated anode voltage.

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

1950 Sylvania

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Characteristics

Phosphor
P4
Deflection method
Magnetic
Focusing method
Electrostatic

Data set 02

1965 Sylvania Electronic Tubes Vol3

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Characteristic

Heater voltage
6.3 V
Heater voltage ............ 6.3 Volts

Other

Maximum Anode voltage
22000 V
Maximum Anode voltage ........ I . 22,000 Volts H ,-in H
Maximum Grid No. 2 Voltage
700 V
Maximum Grid No. 2 Voltage ...... 700 Volts
Minimum Grid No. 2 Voltage
200 V
Minimum Grid No. 2 Voltage ...... 200 Volts SYLVANIA ELECTRIC
After Equipment warm-up period
300 V
After Equipment warm-up period . 300 Volts PAGE 1 OF 3
Anode voltage
16000 V
Anode voltage ............ 16,000 Volts
Grid No. 4 Voltage for Focus6
0 V
Grid No. 4 Voltage for Focus6 ..... 0 Volt
Grid No. 2 Voltage
300 V
Grid No. 2 Voltage .......... 300 Volts
Cathode voltage Required for cutoffs . . +32 to +
60 V
Cathode voltage Required for cutoffs . . +32 to +60 Volts

CircuitValue

Grid No. 1 Resistance
1.5 Mohm
Grid No. 1 Resistance ......... 1.5 Megohms Max.