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Specialized - Cathode Ray ·CathodeRay

DR42

Philips or Mullard oscillography CRT with electrostatic beam control and a greenish-yellow long-persistence screen. Its lingering trace is intended for waveform measurements and instrument displays requiring extended visual retention.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized
Sections
1
Base
-
Socket code
-
Base pins
-
Nominal heater
6.3 V / 400 mA

Description

The Mullard DR42 is a high-vacuum electrostatic oscilloscope tube with an approximately 1.5-inch screen and long persistence phosphor.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
-
Base pins
-
Nominal heater voltage
6.3 V
Nominal heater current
400 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
800 V

High-vacuum oscilloscope CRT; phosphor suffix family differs by luminescent colour/persistence.

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

1951 Mullard Valve and Service Manual

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Characteristic

  • Screen Colour / Persistence

    Long persistence

  • Focusing Method

    Electrostatic

  • Deflecting Method

    Double Electrostatic

Other

  • Anode Voltage

    800 V

  • Focusing Electrode Voltage Minimum

    200 V

  • Focusing Electrode Voltage Maximum

    300 V