Skip to main content
Tube Tinker — Electron Tube Database
Alternatives & variationsDownload PDF datasheet

Specialized - Cathode Ray ·CathodeRay

3KP4

Three-inch cathode-ray tube for oscilloscope and instrument display service, using electrostatic focusing and electrostatic deflection. Its P4 screen designation identifies the phosphor variant within this compact oscillographic family.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized
Sections
1
Base
-
Socket code
OCTALCRT8
Base pins
-
Nominal heater
6.3 V / 600 mA

Description

Sylvania 3KP4 direct-view oscilloscope CRT with electrostatic focus/deflection; P4 white, short-to-medium persistence. Published maximum ratings, capacitances, and typical operating conditions were extracted from the supplied datasheet.

Socket description

Octal 8-contact CRT base

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
OCTALCRT8
Base pins
-
Nominal heater voltage
6.3 V
Nominal heater current
600 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
2750 V

CRT-specific electrode voltages, deflection factors, capacitances, focus/cutoff data, and other published electrical values are stored as section parameters because the promoted section columns are primarily conventional valve fields.

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

Characteristic

  • Phosphor

    P4

  • Focusing Method

    Electrostatic

  • Deflecting Method

    Electrostatic

Other

  • Maximum Anode No. 2 Voltage

    2750 V

  • Typical Anode No. 2 Voltage

    2000 V

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 Current

    600 mA

  • FocusingMethod

    Electrostatic

  • DeflectionMethod

    Electrostatic

  • Phosphor

    P4 white, short-to-medium persistence

  • MinimumUsefulScreen

    2.75 in

Other

  • Anode2VoltageMaximum

    2750 V

  • Anode1FocusVoltageMaximum

    1100 V

  • GridNegativeBiasMagnitudeMaximum

    200 V

  • GridPositivePeakVoltageMaximum

    2 V

  • PeakHeaterCathodeVoltageNegative

    140 V

  • PeakVoltageAnode2ToDeflectionPlate

    550 V

  • Anode2Voltage

    2000 V

  • Anode1VoltageForFocus

    320-600 V

  • GridVoltageForCutoff

    -38 to -90 V

  • DeflectionFactorPlates1_2

    100-136 V/in

  • DeflectionFactorPlates3_4

    76-104 V/in

  • GridCircuitResistanceMaximum

    1.5 Mohm

  • DeflectionCircuitResistanceMaximum

    5 Mohm

  • Anode2PowerInputMaximum

    6 W

Data set 03

1971 RCA HB3 Binder 1 of 7

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Characteristics

  • In general, operation of the 3KP4 at an

    3 V

    Published CRT datasheet value; where a source row has several numbers they represent its separate limits or operating conditions.