When detecting very small rf signals is it possible a switching pre-regulator will present a electrically noisy environment (all those nasty harmonics) or can they be *completely* screened or perhaps remotely located to eliminate the noise problem. If remotely located, what would be a typical distance. I ask as I have seen a receiver setup where all the psu's are linear, not a switching mode power supply anywhere in sight. I thought it would have been much cheaper to go with switch modes but the designers chose the expensive option. (expensive in my calculations) On a related issue, I would guess that psu's in sensitive test equipment like spectrum and network analysers would only use linear psu's. So my question is can switch mode power supplies be used in electrically sensitive environments. Can quiet switchers be produced or effectively shielded. Cheers Justin On Tue, Oct 21, 2008 at 2:43 AM, Olin Lathrop wrote: > ala n smith wrote: >> Yes..I know a switcher will do the job, but there are reasons for >> using a linear in this application (low noise, RF, AF). And its not >> my design, I'm just trying to circumvent the power problem before it >> becomes an issue. >> >> The good ol 7818 and such in the TO-220 package are only rated to 1A, >> but I need closer to 2A. Anyone know of a device, doesnt have to be >> that package, that can go upwards of that current load? > > What voltage is it starting with. Power dissipation may be more of a issue > than current. > > Maybe a switching preregulator followed by a linear if you really need > quiet. > > > ******************************************************************** > Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products > (978) 742-9014. Gold level PIC consultants since 2000. > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist