DEC H744 +5 supply

So, two more questions (if you have the time): I can see that there's a nice synergy between the switching concept and the buck converter (since the switch does exactly what the buck converter needs, in terms of turning the input current off and on), _but_ - are there switching supplies that operate the way I described (up-convert the frequency, then use a transformer to get directly to more or less the right voltage)? I.e. without needing to use a buck converter to do the conversion from low current at higher voltage to higher current at lower voltage? (Although I guess the coil for the buck might be cheaper than the transformer - even though the use of a high frequency would reduce the size of the latter - making the buck approach superior.) To put it another way, there's no _necessary_ connection between the switching concept, and the buck converter is there? Does that mean it is in theory possible to stick a buck converter on the output of a linear supply to do the V1I1-> V2I2 conversion? (Although I know it's probably a stupid design, because you'd still need some sort of switcher for the buck converter, so the linear supply would be basically pointless.) Right, I knew bipolars had the fixed drop, but I hadn't made the connection to that being the cause of the large amount of heat needing to be dumped. Useful enlightenment! Here: http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/jpg/H744.tif http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/jpg/H744.jpg Thanks to everyone for taking the time and energy to reply! Noel