Don't throw away that old charger for your devices you no longer need. It contains 2 different sizes of copper wire. To get at it you 'll need to cut the cover off. Use whatever method necessary. Don't worry about damaging the wire. there will still be plenty. What you have in these chargers are transformers that step down the voltage from household 110 to whatever your device needs. The wire sizes depend on the ratio between the primary and secondary and the amount of current needed by the device. Old relays can also yield wire you can use. If you don.t have an unused charger go to a thrift shop. They usually have a variety for a dollar or so. Generally the smaller the charger the smaller they wire.