Recent content by woollymac

Why do transformers hum? Is it the iron core vibrating & if it is what is it that makes it vibrate? Is it the little atomic magnetics in the iron changing directions with the ac? Can anyone enlighten me?

Thanks - easy when you say it like that.

The frequency of UK mains electricity is 50Hz. I know that this means there are 50 cycles per second & so it must change direction 50 times per second but a colleague is adament that this means the current reverses direction 100 times per second. I just can't get it. Can anyone explain this...