I wanted a power supply to power my two Canon A590IS cameras for the book scanner. The cannon ac adapter kit ack800 are $37 each. I have seen them spec at 3V and 3.15V 9W. I had an old PC power supply rated at 12V, 5V, 3.3V and -12V. I decided to use the old PC power supply and it took some time to get it to work.