Most batteries you throw out are not dead – they just stop working on most devices after 20% of their voltage is used. If you’ve got some random electronics scraps hanging around, you could not only revive these dead batteries, but also make them work for electronics that require a higher voltage.

All you need to learn is a simple Joule Thief circuit and a few points about how batteries work, and you’ll have a ready-to-use power source in just a few minutes’ time. This workshop will teach you how.