HI all, I am a hobbiest. This power project is way to harnest the power of usb connectivity. I have a ad to dc transformer with a usb connector. I want to charge a 9 volt battery. I think I need a step up transformer in my device or would I be able to use an op amp Ic to change the output to 10 volts needed to charge the battery? How would I go about making it a smart charger to have it shut off thn the battery is full? Am I just deaming that a Usb transformer could charge a 9 volt. I know it could do AA or AAA with a 5 volt regulator. I think I need to use a varible voltage regulator.
