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8CP2

Eight-inch P2 electrostatic cathode-ray tube for oscilloscope and special-purpose instrument display, with post-deflection acceleration, a 7.5-inch useful screen, and typical 4 kV final-anode operation.

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 P2 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
P2
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
Blue-green / green afterglow
Persistence
Long
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
P2
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