This reminds me of the electronics lab we had in school. They had electrical components like resistors and caps in transparent little boxes with banana plugs.
The idea was that you'd plug those boxes into bread boards.
Some engineering genius decided to place the plugs exactly the same distance apart as the holes in a standard German power socket though, which enterprising students quickly found out.
None of the caps in that lab worked, all blown up by 240V AC.
The recent reduction in the price of nickel cadmium batteries has led to increasingly widespread use of these energy sources. The following circuit, which uses a 5 5 5 IC, is a simple but effective automatic charger for these popular batteries.