A car voltage generally is 12 Volts. How about when you want to connect non 12 volts devices into your car? The circuit here is the solution. Even the circuit is design for a car apppliance, it does not seem it can’t be used for another purpose.
Source : http://www.geocities.com/dsaproject/electronics/cook-book/cook-book.html
Source : http://www.geocities.com/dsaproject/electronics/cook-book/cook-book.html
