Asklemmy

43959 readers

1196 users here now

A loosely moderated place to ask open-ended questions

Search asklemmy 🔍

If your post meets the following criteria, it's welcome here!

Open-ended question
Not offensive: at this point, we do not have the bandwidth to moderate overtly political discussions. Assume best intent and be excellent to each other.
Not regarding using or support for Lemmy: context, see the list of support communities and tools for finding communities below
Not ad nauseam inducing: please make sure it is a question that would be new to most members
An actual topic of discussion

Looking for support?

Looking for a community?

Lemmyverse: community search
sub.rehab: maps old subreddits to fediverse options, marks official as such
[email protected]: a community for finding communities

~Icon~ ~by~ ~@Double_[email protected]~

founded 5 years ago

MODERATORS

[email protected]

399

Do you often hear the ringing of switching power supplies and devices when you are in a quiet space? (lemmy.world)

submitted 9 months ago* (last edited 9 months ago) by [email protected] to c/[email protected]

149 comments fedilink hide all child comments

I'm curious, how many people are aware of these sounds. I have designed, etched, and built my own switching power supplies along with winding my own transformers. I am aware of the source of the noise. So, does anyone else hear these high frequency sounds regularly?

you are viewing a single comment's thread
view the rest of the comments

[–] [email protected] 3 points 9 months ago (1 children)

Well the flashing light is just a tiny low current neon tube that can't hurt anything. The main thing to worry about with power strips is that they securely hold the connectors in place and not overloading them with more than their rated power, and the power of the circuit they are attached to in your home.

Switching power supplies for cheap consumer stuff are usually operating in the 20-30 kilohertz range. This is just outside of the audible range. What you are hearing is usually the windings or powder ferrite core of the miniature transformer physically vibrating. The audible sound is likely some lower order harmonic resonant peak that is in the audible range.

At the manufacturing level, the frequency of switching can be tuned to avoid unwanted noise, and the magnetics can be potted in a resin or other techniques used to dampen the vibrations. If you build your own power supplies like I have, they tend to make a lot more noise at the first prototype stage.

[–] [email protected] 3 points 9 months ago

It's all Science Magic to me. I am continuously thrilled that the world is filled with people who are much smarter and more curious than I am.

I'll sleep a little better knowing the quiet strip flickering under my aquarium isn't a ticking time-bomb though.