Switched Mode supplies -versus- good old Linear designs - Page 1
Forum section: electronics / testgear

author: Hr_Satch
author_rank: Contributor
timestamp: January 23, 2025, 08:50:02 pm
content: Hello, I'd like to ellaborate some thoughts on to thein my points of view: ALL to overly use of so-called SMPS .I used to repair and maintain Atomic Mass Spectrometers,and these expensive machines, still often applie for in the end suppliesfor some good Linear series regulators for the different power supply voltages.And I think, simply because of the less distortion,inherent to the very-very low CPS signals to work with.I think the same happend with good reliable analogue electronics designs,and the also all over too focused on software applications nowadays.My peursonal biggest experience in computer problems:first aid is a re-boot of the damn thing. 95% it works.In German they say: "Ein Reboot, magt alles gut"In the early days analogue Radio broadcasts were just sometimes somewhat distorted.Now with DAB+ it OFTEN just goes OFF, out of the air.Finish, slush, until a reboot of the mixing tableNow back to the SMPS, didn't they just won more terrain, because of the cheapiness ? ? ?And weight perhapse? The linear transformer is ofcourse also more expensive.But they all commonly fail -some pritty soon- often on their switching capacitors.And/or capacitor related semiconductors breakdown.And they even distort my DAB+ radio, just because they emit havoc.And it are JBLs.So I am into the back to linear 5V designs, with some good old 7805's.USB_v0.0The only Linear supplies I have seen that failed, after regular proper use,are the ones from >40years and older, with often merely dried out caps, but that's it.And with a good design, one can also reach proper efficiencies.In the end it is never good for any PSU whether it is a Linear or a switching one,to let them always powered on, and/or in High Temp ambients, . . .And, yes, okay, you've got the flexibility of lots of different supply voltages out of one block.Back in my school days: SMPS was rather exotic, and were afraid from it:due to its complexity and Lethal voltages.However nowadays, thats the first thing I'd inspect :-?Moreover, Audio and sensitive equipement still prefer Linear voltages supplies above the switchers.And they last for decades, when proper cooled, and taken care off <in terms of not overloading,etc...)Nowadays they even put µProcessor in my Hammer-Drill, the damn thing has some useless slowturn-on thing in its rotational speed controlling switch.Do use it hard -once- at it starts emitting smoke and smells, . . .Atleast they'd give the user/buyer the option to turn that mode off _period_.Is this so-called evolution, I defenite don't think so.Nowadays with ABS, for the common people that brake pedal is merely a push button.And now with electric vehicles, nobody of the newbees can drive a stick shifter anymore.Away goes our proportional regulating skills.And than there is folks fearing we are going to get controlled by robots, haha, LoLHaha, I am afraid it is emminent to our non-technological education in general.Some part of our electro-technical evolution is really great, BUT . . . i need to shift my wordsMost people would benefit from not so dependancy onto electronic gadgets, etc . . .

author: tautech
author_rank: Super Contributor
timestamp: January 23, 2025, 09:27:05 pm
content: There's a place for each.OP, move thread to General Chat.....

author: colorado.rob
author_rank: Frequent Contributor
timestamp: January 23, 2025, 11:15:05 pm
content: Quote from: Hr_Satch on January 23, 2025, 08:50:02 pmAs someone who does RF digital signal processing, at the same power level, the analog radio signal would just sound like pure static when the digital mode cuts out. An analog FM station would be squelched long before the digital signal cuts out. All you are seeing is the difference between a very smooth SNR roll-off in the analog world to a very steep SNR roll-off and sharp cut-off in the digital world using error correcting/detecting codes.Keep living in the past at your own peril.

author: blackdog
author_rank: Frequent Contributor
timestamp: January 26, 2025, 12:44:16 pm
content: Hi,This same kind of discussion is now running again on Circuitsonline.net, a Dutch electronics forum.There too, the one who makes it clear that SMPS are not blissful, is put away as old-fashioned, you are not keeping up with the times etc. blah, blah, blah.If you measure a lot on your workbench, you know what a horror SMPS Power Supply can cause.For the record, I am very happy with SMPS techniques,otherwise I could not be sitting here typing this during my lunch on my nice laptop via a small mains power supply.Why post these limited views here every time.Anyone who develops anything knows the negative characteristics of SMPS.It is a very limited view to keep posting on this and other electronics forums that someone should choose SMPS because it saves losses, small and cheap.The negative implications are often forgotten to be explained.Normal SMPS types for LAB useOften very large capacitor value across the output terminals does not help with current limitation.Slow regulation propertiesAnd almost all of them are EMC lighthouses.Lots of common mode interferenceThe SMPS used in many measuring devices has usually had a fairly long development time that the SMPS in the device itself causes little or no interference.But then it can still provide interference to other devices via ground.I ended up purchasing two battery powered Function Generator to get rid of some of the interference, this along with two battery powered scoops.And yes I know, they are full of SMPS power supply's.The moral...Please tel the whole story if you want to give a good advise.PSAbout modern stuf as example a carAll sorts of things in e.g. modern cars full of computers....Crass of media/GPS systems so you may re-enter your route on the highway.Error lights where you first have to study what the light is all for, sometimes it has four functions.Important functions in a car that go through a computer that are actually better done by hand.Info display's that are not turned toward the driver, etc, etc.Yes i know, i'am old, i can't handle it ect, my view is that it is just poorly designed, just like most SMPS Power Supplys for on the workbench.Kind regards,Bram

author: Hr_Satch
author_rank: Contributor
timestamp: January 26, 2025, 07:05:46 pm
content: Hey all, a bit late with my respons,anyways Thanx Bram aka Blackdog,I think we are on the same track with thinking/observations thru the years of experiences & evolutions, . . .i don't know why I felt the urge in posting this last,moreover I don't think Forums are my cup of game.So much overall negativity, when one thinks out-of-the -box,or tries to bring back different thoughts ? ? ?Or lots of members having nothing else more to do with their time,than wait to spread their banter.I thought this was going more into the electronixs, ideas, developments, . . .Help assist in repairs,For that other (-NEG-) stuff, they've got socalled 'social' media, I thought,like the Boek-of-Facedes, or Kwetter-X, . . .I don't have the energy for such, just am an electronics enthousiast,that likes thinkering with everything that has a wire and voltages inside them.I get really discouraged of such negativisme onlineAre U really the only one that also experienced bad things with SMPS ?