Beam trapping voltage

[Grahame]

I have noticed this phrase on a few CRT datasheets, such as 4EP1 Page 2

https://frank.pocnet.net/sheets/198/4/4EP1.pdf

does anyone know what it means please?

Ta Grahame

[Dekatron42]

It says "In order to obviate..." on page 3 where it explains that function in a short text. Here's another explanation of the use https://www.kimballphysics.com/PDFs/general_options_pulsing_blanking.pdf. You can leave the beam turned on, not turned off by the grid or by other means, and have it locked (trapped) onto the beam trap so that it won't illuminate the screen, it is usually easier to see a single fast pulse on the screen then as the screen is not illuminated by the beam after the pulse has been displayed. Here's a patent discussing the beam trap: https://www.google.com/patents/US3867668

/Martin

[Oscilloclock]

That's very interesting - so this is similar to deflection blanking, but without a special deflection blanking electrode? It's designed such that the X electrodes provide that function, and you just intentionally drive the beam into one of the plates?

Aaron