With the advent of superior rechargeable battery technology these days, gone are the times where you ripped open a pack of AA or AAA batteries to replace those dead ones, where the latter are then thrown out into the garbage bin without giving any more second thought to what would happen to them batteries. Well, Eneloops are fun to have and a whole lot more economical, but if you so happen to have some non-rechargeable AA batteries in your home (AAA will do fine, too), why not let them have a go at the Joule Thief?
The whole idea behind the Joule Thief would be to make sure it forms a complete circuit with your drained batteries, lighting up an LED in the process while draining whatever is left of the battery’s power to make sure it is truly empty before you throw it away. Not the most useful of devices since it cannot store those remnants of energy elsewhere for us, but at least you can sleep easy knowing that you did not waste any of the juice within.