this post was submitted on 04 Jan 2026
173 points (93.5% liked)
memes
18818 readers
1354 users here now
Community rules
1. Be civil
No trolling, bigotry or other insulting / annoying behaviour
2. No politics
This is non-politics community. For political memes please go to !politicalmemes@lemmy.world
3. No recent reposts
Check for reposts when posting a meme, you can only repost after 1 month
4. No bots
No bots without the express approval of the mods or the admins
5. No Spam/Ads/AI Slop
No advertisements or spam. This is an instance rule and the only way to live. We also consider AI slop to be spam in this community and is subject to removal.
A collection of some classic Lemmy memes for your enjoyment
Sister communities
- !tenforward@lemmy.world : Star Trek memes, chat and shitposts
- !lemmyshitpost@lemmy.world : Lemmy Shitposts, anything and everything goes.
- !linuxmemes@lemmy.world : Linux themed memes
- !comicstrips@lemmy.world : for those who love comic stories.
founded 2 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
Look up how a CRT works. As the beam draws picture fields, it moves downwards across the screen driven by a 59.94Hz sawtooth wave. The generator of this sawtooth wave needs to be synced to the vertical blanking interval between fields. "Vertical hold" refers to how long the oscillator waits before the window in which it can accept the sync pulse. Too soon and the picture scrolls down, too late and the picture scrolls up (however, slightly too late, as long as 1/59.94 seconds is still within the window, is fine and the picture can stabilize after one slow scroll up).
Seeing almost two copies of the picture means V-Hold is very late and the vertical oscillator is running way too slow. About 30-40 Hz, very flickery to the person taking the picture!
Ah, thanks for the rundown!