![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
Sometime in the 1970s (before the Transformers toys and associated cartoon) my father acquired a few 15,000 volt transformers used for "neon" signs. They look something like this:
[source.]
These are the things that not only light up neon (and other gas) tubes, including old fluorescents that won't ignite on 120 V any more, but also make the Jacob's Ladder or be part of the power supply for high voltage equipment such as a CO2 laser. This is one of the "dangerous" things I grew up with, but as it was explained, "There are no really dangerous things, just dangerous people." If you think first and are careful, there is no problem. I 'played' with high voltage, but I wasn't reckless with it. Chances are the most dangerous part to me - or anyone else - was not the easily averted shock risk, but the build-up of ozone when there was arcing.
We found it sort of sadly amusing when one day in the 1980s a young neighborhood kid pointed at row of the things and asked what they were...
Kid: What are those?
Pa: Transformers.
Kid: *stares at them for a bit* What do they turn in to?
I never followed that cartoon and am utterly uninterested in it. I still think of the electrical device when I see or hear the word transformer.
15,734 Hertz is the frequency of a television's horizontal scan, at least NTSC (the current US analog TV standard). It's within the range of human hearing, at least for those with healthy ears that haven't been abused. And if things are as they should be, those two facts won't come together.
Alas, not everything is always as it should be. A TV with a traditional picture tube (rather than an LCD or plasma display or such) needs a transformer to deal with the horizontal scanning and this can be a problem. A transformer isn't just wires wrapped around metal, but usually wires wrapped around a bunch of pieces of metal insulated from each other. If the thing is old or just cheap, it can "sing" as a strong signal goes through it, vibrating all those bits of metal.
The result is an annoying high-pitched squeal or shriek that not everybody can hear. It can lead to conversations like this:
"The TV is on."
"No it isn't."
"Can't you hear it?"
"No."
"You must be going deaf."
"You're just hearing things."
It's not just TVs that have this. Computer monitors, at least older ones, can have this problem as well, though often at a different pitch. Such sounds are often on the edge of hearing and seems more sensed than outright heard. I used to walk into a school computer room where everything was supposedly off... and walk right to the one monitor that had been left on as it was, to me, screaming.
