yampire
Newbie
I want to build a power supply from a battery source for my internet modem. My modem is rated as DC 12V-2A. Suggest me the way i can do that. I read about the LM7812 regulator but they say that it is a loss of energy but it can provide constant 12 V. So help me to find solution of my problem I want to power on the modem at least for one hour on battery. What type of battery will i be needed?