2012/06/292012/08/12 By admin In Joule Thief SMPS DC-DC 2012-06-29 Buck 9V to 5V DC-DC Converter I drew these in SWCAD III back in 2005. I haven’t built it yet. The original used a PMOS FET, I just wanted to put out a version that uses a much easier to get NMOS FET.