What you say is true, but the cases you bring up are not the same. The teensy regulator providing power for a processor is designed with pretty solid knowledge of the behavior of the load. The + 8 Volt supply in an S-100 box is a completely different thing, with loads which vary widely from one application to another, and, for that matter from one day to another. If you reversed the bias on the little regulator on a processor, the current stored in the processor would be negligible. If you have a memory circuit on an S-100 card, you probably have forty small capacitors and half a dozen larger ones (e.g. 33 uF) which would be sourcing current to the 7805 regulator(s) while the input now sources current to the disk drives or whatever other low-impedance loads run from that supply. I'm with you about the use of switchers which save on energy and reduce waste from dissipation. However, the proposed "booster" hasn't been thought through yet. They're not very cost-effective, nor do they offer much power per buck. The problem with linear supplies is not their intolerance of high voltage inputs, but rather, my intolerance of their high temperature when operating at a high input/output ratio, as the regulator dissipates it all as heat. That's not likely to happen here, however. Dick -----Original Message----- From: jpero(a)cgocable.net <jpero(a)cgocable.net> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Tuesday, August 17, 1999 4:50 PM Subject: Re: imsai 2 <classiccmp(a)u.washington.edu> 7805. this on