How to Make a USB Power Adapter

By Norm Dickinson

An increasing number of consumer electronics, such as MP3 players and GPS devices, can recharge their batteries from a USB cable plugged into a port on a computer. Many come with power adapters that plug into the wall or car and have a mini-USB connector on the other end specifically for this purpose. Make a USB power adapter to charge and power these devices directly from a desktop or laptop computer, or from any AC outlet, and never be without a source of power.

Things You'll Need

  • 4-conductor copper data cable
  • Wire cutters
  • Wire strippers
  • USB connectors
  • Helping hands soldering aid
  • Electronic soldering iron with stand
  • 60/40 tin/lead solder or lead-free electronics solder
  • 120V AC to 5V DC .5A transformer

USB to USB Power Adapter

Step 1

Cut a piece of cable to the desired length and use the wire strippers to remove about 1 inch of the outer insulation from each end.

Step 2

Strip the tip of each individual conductor back about one-quarter inch. Give each conductor a quick twist between the thumb and forefinger to keep the strands from getting tangled or bent prior to soldering.

Step 3

Place the desired connector into the helping hands soldering aid and preheat the soldering iron for a few minutes.

Step 4

Clip the first wire into the available clip on the helping hands soldering aid and adjust it so that it is lined up with pin 1 on the connector exactly where it needs to be soldered.

Step 5

Place the tip of the soldering iron onto the conductor and press down on the wire to hold it against the connector, making sure it does not dislocate the conductor, and touch the tip of the solder against the conductor until a small amount of solder melts into the junction. Quickly remove the soldering iron and the solder. Inspect the solder joint for a solid connection.

Step 6

Repeat for each pin on the connectors using one conductor for each pin on the connector.

Step 7

Remove the connector and visually inspect it for shorts or loose connections. Attach the plastic hood to the connector.

Step 8

Place the connector for the other end of the cable into the helping hands soldering iron. Solder each conductor onto the same pin number on this end of the cable using the color coding of the conductors as an indicator. The result will be a cable where pin 1 on one end corresponds to pin 1 on the other end, and the other pins connect in a similar manner.

AC to USB Power Adapter

Step 1

Cut a length of cable and strip the outer insulation back about 1 inch from each end.

Step 2

Cut the green and white conductors off even with the outer insulation on each end of the cable, leaving only the red and black conductors protruding 1 inch from each end.

Step 3

Strip one-quarter inch of insulation from the each end of the red and black conductors.

Step 4

Solder the red conductor to the positive output on the 120V AC to 5V DC .5A transformer on one end of the cable and to pin 1 on the USB connector on the other end of the cable.

Step 5

Solder the black conductor to the negative output on the transformer and to pin 4 on the USB connector.