If it's not a design issue, then it must be a component quality issue, with some components just not up to spec.As an important material for many practical and research applications, porous silicon has attracted interest for decades. In my case, it's apparently (some component in) the first supply that is causing the noise, but presumably, both supplies use similar components, and other examples may have a similar (and similarly) defective component in the other supply. I'm assuming there are actually two power supplies in most/all? laptops and their descendants including my XPS12 - one that regulates the incoming power from the AC Adapter and charges the battery, and a second that supplies power to the main board - probably in several different voltages. Seemingly from somewhere near the top rows of the keyboard, but it's very hard to say definitively. But, just to clarify, the noise isn't from the Adapter, it's from the laptop. I have not experienced the noise without the AD Adapter being plugged in. So far, it's a requirement in my case - there is no noise unless the adapter is connected (and powered on).įor other posters in this thread, not so sure as they don't seem to have stated this. Please also private message me with the service tags of your systems as engineering may wish to capture some systems for testing.Ĥ. Please let me know if these assumptions are correct or not. Having the AC adapter plugged in could possibly cause the noise.Windows doesn't need to be running for the noise to occur.The noise doesn't appear to be coming from the speakers.Thanks for your involvement in this thread. Transformers are frequently vacuum-dipped in epoxy or similar to fill up all the spaces inside the windings and between the cores, to prevent this kind of noise. It's this minute movement that gives rise to the noise, so a lot of effort is usually spent in making sure that the windings (and cores) cannot move. The reversing currents in the windings cause the magnetic field to reverse - which means the magnetic force on the windings also reverses, thereby creating the possibility of the windings moving slightly. Many people will remember the sound early camera flash units used to make as they charged up - starting at low frequency and increasing until virtually inaudible when fully charged. It's due to the magnetic field inside the inductor being reversed at high frequency - which is essential if you want to transform voltages and currents in a small device. Maybe the chip you are looking at is actually an inductor - these days its getting harder and harder to tell! Normally, this kind of noise is generated by minute movements inside coils - as an earlier poster has suggested. If the chip is some kind of hybrid, that would be possible. Regarding the source of the noise, I think it would be fair to say it's uncommon and fairly unlikely for an ordinary chip to be the source.

Xps peak components fill