AC adapter Noise

Hi, I have a problem with my Clevo D900C(Sager 9260)'s adaptor, I have 2 of them just in case, but recently when I plug them into the wall, they start (both) making a very low noise in the union of the adapter and the cable which goes to the pc, like a bird singing (the only thing that comes to my mind to compare), now is this somenthing to worry about? Since It happens with both of them. What should I do?

Thanks in advance.

KireruX

 

Is the noise more like a chirping (tweet, tweet, tweet) or a humming (hmmmmm)?

 

more like a humming.

 

Inside, is a transformer. Transformers work by passing alternating current through across a magnetic field, with a different number of coils on each side of the field.

Transformers often 'hum' due to the nature of how they work. I can go into the exact physics of how a transformer works if you want because I really enjoy it....

 

A little cooks' tour would probably be useful, since ac adaptor noise questions do come up from time to time, and since it can be difficult to identify the benign humming of an ac adaptor that's still within spec from an ac adaptor that has gone out of spec and which is making worrisome noises that are indicating the need to replace the ac adaptor.

 

yeah, but it's gettin louder i think, i need to try the other now, thanks for the info, if u really enjoy it I would like you to go so I can learn a bit more about it.

And there is no chance that it could hurt my pc????? please this is more important

 

the humming is how I know "IT'S ALIVE!!!!"

 

Thanks

Basically, a transformer is something that can increase or decrease alternating currents (AC). Two wires are wrapped around two sides of an iron square which has a hole in the middle. When alternating current flows through one coil, it sets up an alternatic magentic field in the core and therefore, it will induce a voltage in the output coil.

Hope this helped a bit Let me know if you need clarification. This effect can often cause a humming noise but shouldn't be TOOO noticeable.

 

When I put my ear to my NP5793 AC adapter, I hear a buzzing noise, almost exactly the same as you hear around high voltage power pylons.

This is funny, because my old Dell Inspiron 9400 doesn't make any sounds at all...

 

Thanks Again, im happy I asked, That was some Excellent explanation in just a few words, couldn't ask more than that... Acutally I can xD!

There is any chance that my PC would be affected by A bad AC Adapter?

Thanks to you all again you have been A great help

 

What is it about the physical construction of a transformer that causes noise, e.g., the humming we all hear when we walk past an eletrical transformer in the street, does the quality of the materials used play a role in the noises generated, and at what point does a sound go from being just an innocuous by-product to being an indication of imminent failure?

 

The quality of the materials used, the type of the transformer,interferences with other electrical or magnetical fields, all play a huge role in the noise you hear in the background. Using better ones helps,but they`re costly and sometimes not justified.
Electrical Engineer, are you mattireland? welcome to the club

 

The sound is caused by the steel in the middle of the wires being magnetized and demagnetized as the current passes through. It's actually many small sheets of steel and this magnetizing effect causes them to expand and contract which can cause vibrations which cause noise.
If for some reason the steel sheets are defective it's possible for them to vibrate so much they break or become inefficient. But some noise is normal and not a cause for concern. If it's getting louder, it's probably slowly vibrating itself to pieces .

It's been a long time since I studied electrical engineering, so hopefully that makes sense.

 

Makes perfect sense, and is consistent with (a) what I've found piece-meal by googling around on the net and (b) what little (precious little ) I recall from the EE courses I took in my abortive engineering degree attempt about 20 years ago.

I was sort of hoping to prevail upon someone who seems to actually know about these things (I clearly don't) to help put together a sort of cheat-sheet for when to tell if your ac adapter just has a loud purr, or is about to barf up its innards.

 

my transformer gives off a high-pitched sound when it is plugged in, kind of like older TV sets but not quite as high. It stops when I power on the computer, but is quite noticeable until I do.

 

Guys thanks, your really helped me here. Hope I can pay you back one day.

Thanks Again

 

Well, you can send a check for ....:wink: