Delete comment from: Ken Shirriff's blog

Willis said...

Excellent post!

I've been wondering why the presumably high-quality samsung charger that came with my Galaxy Nexus emits an ultra high pitched squeal (which wavers a bit) when plugged in, but that goes away when the phone's plugged in.

Based on your article I'm guessing it's the switching frequency, which you said is usually ~70kHz but varies depending on load, so maybe it dips into the top of the audible range when there's nothing plugged in? I'm still left wondering what's physically resonating to create the sound...

I believe the model on the charger is ETA0U80JBEBSTD.

Jul 19, 2018, 4:15:11 AM

Posted to Apple iPhone charger teardown: quality in a tiny expensive package