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?
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...