As a cyclist and a transformer user, can’t help to notice the similarity of the two. So below is the picture of a mountain-bicycle and transformer taken from my favourite source Wikipedia.
To compare them, look at the table of comparison below:
|A Bicycle||A Transformer|
|number of “teeth” of sprocket||number of winding|
|front sprocket||primary winding|
|rear sprocket||secondary winding|
|gear chain||transformer core|