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Specialized - Cathode Ray ·CathodeRay

8CP1

Eight-inch special-purpose oscilloscope CRT with electrostatic focusing and deflection, post-deflection acceleration, and a P1 screen. Its high-voltage system provides a bright precision trace.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized
Sections
1
Base
-
Socket code
B12A
Base pins
-
Nominal heater
6.3 V / 600 mA

Description

Eight-inch electrostatically focused/deflected special-purpose CRT with post-deflection acceleration and P1 phosphor.

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
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
10000 V

Published maximum ratings and characteristics promoted semantically from the approved source.

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

    P1

  • Focusing Method

    Electrostatic

  • Deflecting Method

    Electrostatic

Data set 02

1965 Sylvania Electronic Tubes Vol3

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Characteristics

  • Focusing method

    Electrostatic

  • Deflection method

    Electrostatic

  • Post-deflection acceleration

    Present

  • Fluorescence

    Green

  • Persistence

    Medium

  • Heater voltage

    6.3 V

  • Heater current

    600 mA

  • Deflection factor plates 1-2

    58 to 81 V/in

  • Deflection factor plates 3-4

    49 to 68 V/in

Construction

  • Phosphor

    P1

  • Useful screen diameter minimum

    7.5 in

Other

  • Typical anode-3 voltage

    4000 V

  • Typical anode-2 voltage

    2000 V

  • Focus voltage range

    540 to 800 V

  • Grid1 cutoff voltage range

    -24 to -56 V

  • Grid1 negative-bias maximum

    -220 V

  • Grid1 positive-bias maximum

    0 V

  • Grid1 positive peak maximum

    2 V

  • Heater-cathode voltage maximum heater negative

    140 V

  • Heater-cathode voltage maximum heater positive

    140 V

  • Anode2-to-deflection-plate peak voltage maximum

    550 V

  • Grid1 circuit resistance maximum

    1.5 Mohm

  • Deflection-circuit resistance maximum

    5 Mohm

Application

  • Application

    Oscilloscope / special-purpose instrument display