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.
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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 Misunderstand> A lady just contacted me and says she can hear her Nokia phone charging -
Normal. I get it with a cordless phone - a really quiet tick.
Ask if the lady has asthma
martin
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.
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
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
Typically its a burst mode charger. bbbrrrzzz, bbbrrrzzz, bbbrrrzzz is usuall what I hear on the AM.
Cheers
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