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Tube Tinker — Electron Tube Database
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Specialized - Cathode Ray ·CathodeRay

633AM

Six-inch flying-spot-scanner CRT with electrostatic deflection, magnetic focusing, and a high-resolution metal-backed screen. Ferranti documentation gives high-voltage anode capability to approximately 25 kV.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized
Sections
1
Base
B12A
Socket code
-
Base pins
12
Nominal heater
6.3 V / 300 mA

Description

Six-inch flying-spot-scanner cathode-ray tube with electrostatic deflection, magnetic focus, and high-resolution metal-backed screen.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
B12A
Socket code
-
Base pins
12
Nominal heater voltage
6.3 V
Nominal heater current
300 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

B12A - 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
25000 V

Ratings, characteristics, typical operating points, and capacitances were extracted from the supplied Ferranti datasheet.

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

1963 Ferranti

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Characteristic

  • HeaterOrFilamentVoltage

    6.3 V

  • HeaterOrFilamentCurrent

    300 mA

  • FocusingMethod

    Magnetic

  • DeflectionMethod

    Electrostatic

  • ScreenConstruction

    Metal-backed

  • UsefulScreenDiameterMinimum

    127 mm

  • GridVoltageForVisualCutoff

    AnodeVoltage/120

  • ModulationDriveFor50uABeamCurrent

    33 V

  • XDeflectionSensitivity

    500/AnodeVoltage mm/V

  • YDeflectionSensitivity

    450/AnodeVoltage mm/V

  • XPlateCapacitance

    1 pF

  • YPlateCapacitance

    5.8 pF

  • X1ToX2Capacitance

    1 pF

  • Y1ToY2Capacitance

    0.9 pF

  • XPlateToAllCapacitance

    4.8 pF

  • YPlateToAllCapacitance

    4.3 pF

Other

  • HeaterCathodeVoltageMaximum

    100 V

  • BeamCurrentMaximum

    200 uA

  • Anode Voltage

    20000 V

  • GridVoltageForVisualCutoff

    -170 V

  • FocusCoil

    900 ampere-turn

  • ScreenResolutionMinimum

    100 lines/cm

  • NormalPeakBeamCurrent

    150 uA