FPGA Central

A lady just contacted me and says she can hear her Nokia phone charging -
like a pulsing sound. Nobody else can hear it but when it is switched on she
registers the sound from some 2-3 metres away. When it is charged the sound
stops. I also know of another person who can hear similar sounds from
electrical equipment. Could this be a low frequency sound or is it something
odd happening...? With the charger on it's own she doesn't hear anything.


M.



--
Posted via a free Usenet account from http://www.teranews.com

really sounds interesting,
may be she has got the sense of
hearing a little more powerfull than all of us, yes think the same case
with that person also

particlereddy



Major Misunderstanding wrote:
> A lady just contacted me and says she can hear her Nokia phone charging -
> like a pulsing sound. Nobody else can hear it but when it is switched on she
> registers the sound from some 2-3 metres away. When it is charged the sound
> stops. I also know of another person who can hear similar sounds from
> electrical equipment. Could this be a low frequency sound or is it something
> odd happening...? With the charger on it's own she doesn't hear anything.
>
>
> M.
>
>
>
> --
> Posted via a free Usenet account from http://www.teranews.com

"Major Misunderstanding" <[email protected]> wrote in message
news:4531cc30$0$19623$[email protected]. .

> A lady just contacted me and says she can hear her Nokia phone charging -
> like a pulsing sound. Nobody else can hear it but when it is switched on
> she
> registers the sound from some 2-3 metres away. When it is charged the
> sound
> stops. I also know of another person who can hear similar sounds from
> electrical equipment. Could this be a low frequency sound or is it
> something
> odd happening...? With the charger on it's own she doesn't hear anything.

Normal. I get it with a cordless phone - a really quiet tick.

On Sun, 15 Oct 2006 19:46:05 +1300, in sci.electronics.design "Major
Misunderstanding" <[email protected]> wrote:

>A lady just contacted me and says she can hear her Nokia phone charging -
>like a pulsing sound. Nobody else can hear it but when it is switched on she
>registers the sound from some 2-3 metres away. When it is charged the sound
>stops. I also know of another person who can hear similar sounds from
>electrical equipment. Could this be a low frequency sound or is it something
>odd happening...? With the charger on it's own she doesn't hear anything.
>
>
>M.
Ask if the lady has asthma

http://www.springerlink.com/content/m268245861vu14t1/


martin

Major Misunderstanding wrote:
> A lady just contacted me and says she can hear her Nokia phone charging -
> like a pulsing sound. Nobody else can hear it but when it is switched on she
> registers the sound from some 2-3 metres away. When it is charged the sound
> stops. I also know of another person who can hear similar sounds from
> electrical equipment. Could this be a low frequency sound or is it something
> odd happening...? With the charger on it's own she doesn't hear anything.
>


Most adults in our industrial society have presbycusis, a fancy word
for hearing loss in the upper register.
Apparently this lady didn't go to rock concerts as a young'un.

kell wrote:
> Major Misunderstanding wrote:
> > A lady just contacted me and says she can hear her Nokia phone charging -
> > like a pulsing sound. Nobody else can hear it but when it is switched on she
> > registers the sound from some 2-3 metres away. When it is charged the sound
> > stops. I also know of another person who can hear similar sounds from
> > electrical equipment. Could this be a low frequency sound or is it something
> > odd happening...? With the charger on it's own she doesn't hear anything.
> >
>

It may be the charger, my daughter can hear the car charger in my car,
it uses a switching supply up around 19 kHz or something, she can hear
it, I can't. It a HIGH frequency sound.

Mark

On 2006-10-15, Major Misunderstanding <[email protected]> wrote:
> A lady just contacted me and says she can hear her Nokia phone charging -
> like a pulsing sound. Nobody else can hear it but when it is switched on she
> registers the sound from some 2-3 metres away. When it is charged the sound
> stops. I also know of another person who can hear similar sounds from
> electrical equipment. Could this be a low frequency sound or is it something
> odd happening...? With the charger on it's own she doesn't hear anything.

High frequency. Nokia (and most other brands) use switched-mode powersupplies
in phone chargers. These operate at a high frequency that is somewhat dependant
on the load.


consider an automobile engine, when it is working hard (accellerating, or
climbing a hill) it makes more noise. These switched mod powersupplies are
the same. Inside is a small transformer and as the electric current through it
is switched on and off rapidly magnetic fields are formed and broken. This changing
magnetism causes it to vibrate, which causes the sound.


the pulsating effect is possibly due to the phone interrupting the charge to
measure the charge level in the battery (this would reduce the load on the
charger momentarily).

Bye.
Jasen

"Mark" <[email protected]> wrote in message
news:[email protected] ups.com...
>
> kell wrote:
>> Major Misunderstanding wrote:
>> > A lady just contacted me and says she can hear her Nokia phone
>> > charging -
>> > like a pulsing sound. Nobody else can hear it but when it is switched
>> > on she
>> > registers the sound from some 2-3 metres away. When it is charged the
>> > sound
>> > stops. I also know of another person who can hear similar sounds from
>> > electrical equipment. Could this be a low frequency sound or is it
>> > something
>> > odd happening...? With the charger on it's own she doesn't hear
>> > anything.
>> >
>>
>
> It may be the charger, my daughter can hear the car charger in my car,
> it uses a switching supply up around 19 kHz or something, she can hear
> it, I can't. It a HIGH frequency sound.
>
> Mark
>

Typically its a burst mode charger. bbbrrrzzz, bbbrrrzzz, bbbrrrzzz is
usuall what I hear on the AM.

Cheers