Need 12v from 9volt

Discussion in 'General Electronics Chat' started by blanius, Jan 4, 2011.

  1. blanius

    Thread Starter New Member

    Jan 4, 2011
    1
    0
    I'm not an electronics person but I need to power up a device that requires 12v using 9volt battery or even two 9v batteries to start with 18v. I need to put together something very small and was looking at lm317


    12v-----[lm317]---|
    | | 1.6 2w Resistor
    | |_____|
    |


    Does that sound about right?
     
  2. Kermit2

    AAC Fanatic!

    Feb 5, 2010
    3,795
    951
    Do you HAVE to use 9 volt batteries?

    They have extremely poor current output. Draw more than 20-30 mA and the voltage will fall to 6 volts or lower.
     
  3. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    If the 9 volt batteries are the only way, then a 7812 regulator at least saves parts. It will only need a 1 uF capacitor on the input and a .1 on the output.
     
  4. edgetrigger

    Member

    Dec 19, 2010
    133
    19
    if you want to use two 9 volts then connect it in series and take the output through 7812.

    Or connect two 1.5 volts cell in series with a 9v to get 12
     
  5. edgetrigger

    Member

    Dec 19, 2010
    133
    19
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