system
Given the following post, respond as if you're commenting on Reddit:
human
Can electrical circuits make noise?

My laptop (UX305C) doesn't use a fan nor a mechanical hard drive, but I hear a very soft kind of zzz - zz -zzz noise in especially quiet environments. What might be the cause of this?

Edit: sorry, the title should say "sound."
gpt
Yes.

Ultimately, for any normal electrical circuit to make a sound, it must cause a physical vibration. However, even circuits with no "moving parts" often have inductors, which are usually just coils of wire. The inductor is there because there are rapidly changing voltages, and inductors will often vibrate in response the the rapidly changing voltages. This is the likely source of your problem.

If you were really curious, what you should do is open up the case, and expose the motherboard. If you put a tube/straw in your ear and move it around the motherboard, you will clearly hear it when you're near the component making the noise. There are various coatings that you can apply which will then stop the movement.