DIY iPhone 3G Charger
- 1). Open the base of a USB charger. Unscrew the screw that usually holds the base halves together, and separate the two halves.
- 2). Solder a 100k ohm resistor to both pins number 1 and 4 (the outside pins on a USB plug) on the circuit board. You are adding two resistors into the circuit.
- 3). Disconnect anything connected to the middle two pins; these pins are usually not connected.
. - 4). Solder each of the loose wires on the two resistors to pins number two and three, respectively. Also connect pins 2 and 3 with solder or wire. The objective is to create approximately two volts on pins 2 and 3. Be careful not to get solder or wire on any other connection points.
- 5). Check the connections: a resistor joining pins 1 and 2; pins 2 and 3 joined by solder/wire; and pins 3 and 4 joined by the second resistor. Verify voltages on each pin with a multimeter if you have one.
- 6). Reconnect the two halves of the charger base, plug in the USB cable, and charge the iPhone 3G.