Why do my batteries emit a high-frequency pitch while charging?

Question

I've only noticed this with my psp and ds lite charger. Whenever they are charging their respective product they emit this high pitch. No one really seems to notice it but me but it just drives me crazy! I'm sure answering this question might just lead to a lesson in how battery and battery charging work.

Answer 1

It isn't the batteries you're hearing. It's the charging circuit. Most of the 'switchmode' chargers run at 10 to 15 KHz and so a few people can hear them.

The newer chargers run around 20 to 25 KHz which means that people can't hear them (although your dog can hear them quite well ☺)

Doug