E EmptyNest Administrator Jan 6, 2013 #1 Calculators, LEDs, and other low-power devices can be run from a very basic battery constructed from a few pennies, zinc washers, and small cardboard circles soaked in vinegar. More »
Calculators, LEDs, and other low-power devices can be run from a very basic battery constructed from a few pennies, zinc washers, and small cardboard circles soaked in vinegar. More »