A noisy LED, or am I going crazy?

[rork]

First of all, let me apologize for this rather lengthy post. It's long, because I wanted to give you enough background, before I asked my question(s).

OK, how many of you guys can hear the electron beams hitting the cathode on a TV or a monitor? I know I've always had this "super power," but I just did some research on the internet and it seems like relatively few people can actually hear it (for example, my wife can't). For those who don't know what I'm talking about, it's a high pitch annoying noise. It's never really bothered me that much--when a show is on TV, I can't hear it, and when there's nothing on, then at least I know when I forgot to turn the TV off (kinda like the beeping thingy in your car, when you forget to turn off the lights... ).

Anyway, my question is (I guess for those who can hear that thing too), have you ever been able to hear it coming from a simple LED? The other day, I realized that I heard the noise in my bedroom, where I don't have a TV. At first, I thought that it was just the TV in the living room (this super-sense has a pretty impressive range sometimes... ), but it wasn't on!? I did a little investigation and I realized that it was the blinking LED on my wireless router that signals network activity. What the hell!? Have you ever encountered this? Has my hearing gotten better for some reason, or am I just going crazy? Or, which is my main question for you guys (and what I fear most), is my router (or at least that one diode) messed up? By the way, I've had this router for about a year now and have never had this problem before...

Thanks in advance!

[eslapion]

OK, how many of you guys can hear the electron beams hitting the cathode on a TV or a monitor?

I could before the age of 30. I have since lost sensitivity to higher audio frequencies.

As for the router, are you REALLY sure this is the source of this high pitch noise? In order for solid state electronic components to start emitting sound, they must be intermittently traversed by electric current strong enough to deform their monolithic cores. This happens, for instance with power MOSFETs used in power supplies or power factor correctors.

Power MOSFETs are switched ON and OFF thousands of time every second in most applications and could produce highly annoying sounds. Some of them can be traversed by currents as high as 100amps. Some of the failed power supplies projects I made a couple of years back used to get all the dogs in the apartment building I lived in go nuts. It also gave a serious boost to my electricity bills...

I really doubt a simple LED could be deformed by the weak currents that traverses it.

[PhotoJim]

I could hear my Commodore 64 running... even if I turned my monitor off I could hear noises when the C64 was manipulating the video image. I can't quite describe the noise; it was subtle, almost like a high-pitched squawk or squeak. I could particularly hear it when the C64 was scrolling 80-column screens (because they were in hi-res mode I suspect).

I haven't tested lately to see if I can still hear it, though.

I can definitely hear televisions being on. It's just as you described, a high-pitched squeal. I may be losing sensitivity to it, though, because a TV got left on in the bedroom a few weeks ago and I didn't notice.

[ral-clan]

Yeah, I used to be able to hear TVs being on as well. I'm not sure if I still can....but I think sometimes I might be able to. I really think it depends on the model of the TV or not, and if it's ailing. Not all TVs make the same high pitched sound.

[ral-clan]

In order for solid state electronic components to start emitting sound, they must be intermittently traversed by electric current strong enough to deform their monolithic cores.

Eslapion, sometimes you say the darndest things!

[PhotoJim]

Eslapion, sometimes you say the darndest things!

We'd better order more Ultimate Expander cartridges from him so that he doesn't have so much time to think.

Jim

[rork]

Hey Eslapion, thank you for your reply!

As for the router, are you REALLY sure this is the source of this high pitch noise?

Yep, I'm 100% sure. When I put my ear to it, it gets louder. When I turn the router off, the noise is gone. When I turn it back on, the noise comes back. Also, it seems like it's getting worse. Now, I can't even sleep when that damn thing is on.

In order for solid state electronic components to start emitting sound, they must be intermittently traversed by electric current strong enough to deform their monolithic cores.

(I agree with the others; this sentence IS powerful! )

So, if I understand correctly, something must've happened to the router. As I said, I noticed that noise only a few days ago and I haven't done anything extraordinary lately, so I have no clue what could've caused it.

I'll have to check if I still have warranty on that router. Man, I can already see the faces of the people I'll be complaining to. They'll think I'm crazy. I'm sure they won't be able to hear that noise...

[eslapion]

In order for solid state electronic components to start emitting sound, they must be intermittently traversed by electric current strong enough to deform their monolithic cores.

Eslapion, sometimes you say the darndest things!

Huh, actually I know that because when I was 15, I did a tour of the montreal metro system. Of course, everyone's favorite question about the montreal metro system is... why does the metro make that 3-tone melody when leaving a station. The answer lies in the power choppers used in MR-73 wagons.

See : http://world.nycsubway.org/canada/montreal/

Huge semiconductors change shape when switched on and off and as the frequency changes, you can hear a loud 3 tone crescendo.

I think it is a bit louder than Rork's LED...

[Mayhem]

In answer to the question in the first post, yes I can hear TVs and monitors being on without being able to see them or even being in the same room. Drives me a bit nuts at times to say the least. It does mean I need to probably switch off more electrical stuff at night to not get bombarded with high frequency sound than other people.

[Mike]

I still can hear the switching power supply that loads the accu of my cell phone... it's an annoying noise, that repeats every second, and lasts for half a second.

And I too know about the 'computing noise'. Most of it stems from parasitic coupling into the sound amplifiers from the data, and address busses. It then reflects regular activities of the CPU. Screen updates at 50 Hz (or less) - for an example, I can hear every frame, that is drawn in Elite. Or transfers on the serial bus: ~400 Hz. And so on.

I need to probably switch off more electrical stuff at night to not get bombarded with high frequency sound than other people.

Silence is golden.

Michael

[rork]

So, I'm sending my router back to NetGear. They promised to ship a replacement within a week. Seems like I wasn't going crazy after all and it was indeed messed up.

The noise has been getting louder and louder and eventually became unbearable (in the end, even my wife could hear it). I also started losing wireless connection at some point. I called the NetGear tech support yesterday and even though in my very first sentence I said "my router is messed up and I need a replacement," I still had to spend over 30 minutes on the phone with the guy. I told him that I'd tried everything and that the router was faulty, but he still tried to convince me that it was my fault and that I was inputting my passcode wrong and stuff like that. Interestingly, he didn't even seem to know what ipconfig was, but still talked to me like I was the idiot.

Anyway, I'm sure glad to have gotten rid of this annoying noise...

[Jeff-20]

Now, what can be done about the voices? My LED keeps telling me to smash other computers...

[rork]

Now, what can be done about the voices? My LED keeps telling me to smash other computers...

That's what my wife said I should've told him; that my router talks to me and tells me to do "bad things." Then, at least, he could've had a real reason to talk to me like I was an idiot...

[carlsson]

I suppose you ended up in first line support, and were not able to convince him to relay you further? You probably need a reference number to get to some more skilled person.