Automatic turn on/off power supply transformer - primary winding

[HackoBoy]

Hello
I have an idea, but I do not know how.
I noticed that the charger for my phone if the phone is not turned on to charge - it does not consume anything. But when I turn on the micro usb connector - then begins to consume.
Now fit a box that will convert unbalanced audio signal into balanced. But the transformer can not fit in the box of the device and the target mount it in an external box. I do not want a permanent transformer is plugged in.

 

[HarryA1]

(1)"I have an idea, but I do not know how."

What is your idea?

(2)"I noticed that the charger for my phone if the phone is not turned on to charge - it does not consume anything. But when I turn on the micro usb connector - then begins to consume."

Find; a statement of fact.

(3)"Now fit a box that will convert unbalanced audio signal into balanced. But the transformer can not fit in the box of the device and the target mount it in an external box. I do not want a permanent transformer is plugged in. "

What is the relationship between  sentence (2) and sentence (3)? What are trying to do in sentence (3)?