This is a multi-part message in MIME format. ------=_NextPart_000_0783_01C12A99.F6EBDCA0 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: 7bit > Requirement > > Step down voltage regulator suitable for powering small low voltage circuits > from a higher voltage supply with a reasonable power dissipation. > > Overall figure of merit = finished cost while meeting design specification. > Costing rules provided below. ................. OK - here's a solution that has been suggested by a friend from the NatSemi LM336 regulator diode data sheet Without going back to my original cost list I estimate that this is about 130 to 150 units cost. (Under $US1 probably with substitutions below). Not too bad. I've pretended that the LM336 here can be substituted with a low cost zener diode - if not the price is significantly higher. I've assumed that all transistors can be low cost general purpose ones BC337 / BC327 as the power level specified in my challenge is low. Also, the output catch diode could be a 1N4148 ! - not what you would normally see in this role but again, the power level is low. Any improvements on this? Russell McMahon ------=_NextPart_000_0783_01C12A99.F6EBDCA0 Content-Type: image/gif; name="Lm336buck.gif" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="Lm336buck.gif" R0lGODlhQwJXAYAAAAAAAP///yH5BAAAAAAALAAAAABDAlcBAAL/jI+py+0Po5y02ouz3rz7D4bi SJbmiabqyrbuC8fyTNf2jef6zvf+DwwKh8Si8YhMKpfMpvMJjUqn1Kr1is1qt9yu9wsOi8fksvmM TqvX7Lb7DY/L5/S6/Y7P6/f8vv8PGCg4SFhoeIiYqLjI2Oh4BfAoOUlJEVmJCQRw+bHp2fm5EOrh uRlhCoF6oHpRyqrByRGbSZvzuqF6+zBrYKobMNqB+svAi2CMy0ls2bBc+6yJ7Cwaq/waGty7aly6 2nt5LV0Bnlsdyf2dgAxcvT37Luou/63MDn2Pc+uabg+sIN1N26eA1P6ds+Zq4D6D5fiRY0cOG8GI Egluuwhx2EKN/+n2BdyYDZ/IF/oe+jr5r5jJaw50oXS4EqO6jxD7DePnz+ZBmNpwuhtVTyfPnMd2 9rM3baRSE/qOCXzpNJ63jFMLMqwpFKm1lhSN3jxa9etWoiWxZgQXlSNZiTihLn27oinMg9y2NpwH UCVInndlaqWL8eHMjmgd+p1rdqhawS8bJoULWVjQxSfr0lM8tKhFooT5ug089i7HrzZ7Cg0p2ivg vz3FThYcOTaJhBSL+tTMauLHcBbDZa0c8mzo4XQpl267GazGckBpCseqW7b0P49trbNwfbr2StVp LMyQcLv48d67NzNPPr369ezbu38PP778+fTr27+PP7/+/fz7+///D2CAAg5IYIEGHohggnbQJhxt 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