It’s a project called snapVCC, and it turns a 9 volt battery into a regulated 3.3 or 5 volt supply. The idea behind snapVCC is simple enough; just add a circuit board to the top of a nine volt ...

This joule thief led or high efficiency LED with 1.5 volt driver is a tried and tested circuit built around some discrete electronics components. A common 5 mm high-efficiency white LED (D1) is the ...