For an index to all my stories click this text
Upon opening I stumbled upon this. I never suspected that they had a fan inside !!!
I added a resistor to the photo as a reference so you can see it is indeed a very small fan.
I attached 3 AA batteries in series to the fan as a power supply. They started spinning immediately. The mystery of the humming sound revealed and ......... I have some real good working fans that can operate at 5 volts.
Moral of the story: do not throw anything away before having a closer examination.
Till next time
have fun
Luc Volders