That old wives tale about switching power supplies is obsolete by at least 25 years. If you buy a radio or TV set look inside. There is certainly a switcher right inside the radio or TV and it is not harming reception.
Yes if yu tried to design you own switch mode supply and did not understand modern design techniques it would likely radiate noise. If yu do build a power supply remember you do NOT want a VOLTAGE regulator you want a CONSTANT CURRENT power supply for LEDs Let the voltage go where it wants I suggest that you MEASURE RF radiation from the power supply before you assume it is bad On Wed, Apr 25, 2018 at 2:48 AM, Erik Christiansen <dva...@internode.on.net> wrote: > Late reply - just back from a week off-net. > > On 17.04.18 11:49, Lester Caine wrote: > > But thinking about the 'off grid' situation, a 12V battery with a low > > dropout regulator could provide lights efficiently. While bigger > > appliances need 'mains', quite a number around here are also 12V > > powered, so 'building from scratch' could a DC supply direct off a > > storage system be an alternate way forward? > > As mentioned upthread, a linear regulator wastes power. But cheap > switchmode power supplies tend to radiate RF, and wipe out radio > reception in my remote rural location. For that reason, rather than make > the aforementioned LED lamp dimmers switchmode, they will be linear > current sinks, and one central very well screened & filtered SMPS will > drop the 48v battery bank to 21 or 22v. The big 10W LEDs I bought on > fleabay for 83c each are like searchlights on 1A @ 10v. Two of them in > series (a pair of matched luminaires) = 20v + 1 or 2v for the linear > current sink, setting 1A max for LED survival. As even 20/22 is 91% > efficiency, I'll go with that for the complete absence of RFI from the > distributed units. > > So long as the circuit breakers or fuses protect the wiring, rather than > the other way round, safety oughtn't be an issue. Nor will arcing, as > MOSFETs will do all the current control. > > Erik > > ------------------------------------------------------------ > ------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
