multiple power supplies

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i'm working on able power battery, or dc power jack. when there attached dc jack, don't want draw current battery. (i'm cheap that)

is easy do? think uno this, i'm software guy , schematic complicated me. :-)

can explain whether feasible , if how go it?

i'm planning use basis each power supply: http://www.sparkfun.com/tutorials/57

thanks in advance help!

- mark

it depends on connect battery , voltage on jack compared battery.
if jack voltage higher battery voltage need seriese diode stop current flowing battery.
if jack voltage lower need fet act switch, see arduino schematic example of how this.


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