Oscilloscope

From Eric

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* From http://www.cfp-radio.com/realisations/rea75/tv2pouces-01.html
* From http://www.cfp-radio.com/realisations/rea75/tv2pouces-01.html
[[File:5LO38I-hv-4.jpg|400px|thumb|none]]
[[File:5LO38I-hv-4.jpg|400px|thumb|none]]
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* From http://www.emartinka.cz/index.asp?IDKategorie=9&IDClanku=18&Akce=clanek
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== Chinese 8SJ31J tube ==
== Chinese 8SJ31J tube ==

Revision as of 15:54, 10 January 2021

Contents

General information about CRT tubes

Some explanations about the functioning of a CRT:

General diagram

The most popular schematic, from Elextronixandmore, using a Hammond transformer. A kit can be bought at Catahoula Technologies. The schematic and the BOM are here.

Elextronixandmore.jpg

Another one solid-state scope from Electronixandmore, without isolation. The voltages are the following:

 HV		350V	Anode Cap
 X1/X2/Y1/Y2	280V	Deflection plates
 A2		270V	Anode 2
 A1		-310V	Anode 1
 K		-665V	Cathode
 G1		-675V	Control Grid

Those values are fine for a 3BP1 tube.

The tubes

5LO38I russian tube

I have bought a russian 5LO38I tube on ebay.

The tube is delivered with a russian notice. Hopefully, someone has provided a german translation translation:

5LO38I-datasheet.jpg

This gives:

  • Filament voltage: 6.3V, 600mA +/- 10% (5.7 to 6.9V)
  • Anode voltage: 1000V (500V to 1100V)
  • Deflection:
    • On X: 0.09 to 0.14 mm/V
    • On Y: 0.11 to 0.16 mm/V
  • Focus voltage : 138V to 300V (<550V)
  • Cathode voltage: (-125V to 0V)
  • G1 voltage: -30V to -90V (-125V to 0V)
  • Voltage between "ablenkplatten" and anode: (-660V to 660V)

You can find several applications of the 5LO38I:

Several schematics to generate the high-voltage power supplies:

5LO38I-hv-1.jpg
5LO38I-hv-2.jpg
5LO38I-hv-3.jpg
5LO38I-hv-4.jpg
5LO38I-hv-5.jpg

Chinese 8SJ31J tube

See Aliexpress (8SJ31 from GuangYi store (Aliexpress).

The datasheet can be found here : http://www.ges.cz/sheets/8/8sj31jv2.pdf

Deflection circuits

Deflection 1.jpg
Deflection 2.jpg


My setup

For the generation of the high voltages, I'll use a 220V/220x2+6.3Vx2 ransformer (bought on AliExpress):

Transformer for tube.jpg

I'll use a Greinacher voltage doubler to generate the -600V. The +220V voltage will be obtained by half-rectifying the transformer's secondary output.

The Greinacher circuit:

Greinacher.jpg

Other schematics


Other topics

Oscilloscope music:

See also:

Personal tools