EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: Azhar on September 19, 2020, 05:43:00 am
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Want to build a bench power supply, and would like to know what are the cons and pros between a Switching power supply and a Linear one!
Thanks
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https://www.youtube.com/watch?v=cM7t1Mpu7s4 (https://www.youtube.com/watch?v=cM7t1Mpu7s4)
https://www.youtube.com/watch?v=qGp82xhybs4 (https://www.youtube.com/watch?v=qGp82xhybs4)
https://www.youtube.com/watch?v=CIGjActDeoM&list=PLBF35875F73B5C9B5 (https://www.youtube.com/watch?v=CIGjActDeoM&list=PLBF35875F73B5C9B5)
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A linear supply is going to be easier to build.
What do you expect to do with the supply? What voltage and current capability do you want? How much electronics building experience do you have?
If it is your only bench supply I would go with a linear one. A dual 20V/1A supply with current limiting would be fine for a first bench supply.
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A linear supply is much easier to build, at least at low to moderate power. A linear supply is usually also lower noise and faster reacting.
The main downside of a linear regulator is that it produces quite some heat and the classical 50/60Hz transformer is heavy. At high power ( e.g. > 50 W) this can make the switched mode supply cheaper and worth the extra effort in the circuit and with EMI.
For a first try one should go with a low power linear supply: it is relatively easy and enough to learn the basics. With modern electronics one rarely needs high power - more like a 3rd supply.
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buy or build the analog one for small currents (with cv/cc protection) and buy the smps one (fixed or variable, upon your demands) for pumping real current after you promote yourself to medium>advanced electronist
sometimes in this business you need 30-50 amps, that's smps days now.
analog is more lab stuff
I was testing hundreds of intelligent motor controllers with dsp or microcontroller core (like 30-80 at once on the power bus) using smps power supplies, never had a failed board from caused by the ps.
is the board is correctly engineered it works with smps, like all the stuff in our houses, smartphones, tablets, laptops.....
real analog good PS are for lab dev nowadays, for those rarely delicate loads.
regards,pierre
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Just a short warning: the lab supply design starting in video 221 did not work well. Combining constant current and constant voltage mode is tricky. A voltage regulator like the LT3080 is not as robust to odd loads as a lab supply should be.
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Just a short warning: the lab supply design starting in video 221 did not work well. Combining constant current and constant voltage mode is tricky. A voltage regulator like the LT3080 is not as robust to odd loads as a lab supply should be.
Is there a project you recommend? My skills are at the beginner level, I have the tools needed to build most small projects. I have a Korad KA3005P on my bench already and I'd like another supply for when I need different voltage/current levels. Thanks!
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You might be interested in this design:
https://youtu.be/jBtNH1EbU8M
It uses the dual LM317 idea to provide current and voltage control - the one in the datasheet.
The voltage tracking and DPDT switch on the output is convenient for op-amp circuits.
He does some performance comparisons of it against a Korad and a cheap switching 30V/5A supply in this video which is instructive in and of itself:
https://youtu.be/RdT-xWC4h4k
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A little more complex and not really suitable for an absolute beginner, the design in this thread is capable of good CV and CC performance.
https://www.eevblog.com/forum/projects/how-this-linear-psu-circuit-works-and-why-it-doesnt/ (https://www.eevblog.com/forum/projects/how-this-linear-psu-circuit-works-and-why-it-doesnt/)
A few variants of it have been successfully built including by myself.
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You might be interested in this design:
https://youtu.be/jBtNH1EbU8M
It uses the dual LM317 idea to provide current and voltage control - the one in the datasheet.
The voltage tracking and DPDT switch on the output is convenient for op-amp circuits.
He does some performance comparisons of it against a Korad and a cheap switching 30V/5A supply in this video which is instructive in and of itself:
https://youtu.be/RdT-xWC4h4k
I've watched the videos and now have something to aspire to. This looks like a fun project, I'm going to have to figure out how I'm going to do some of the case work given what tools I have available. Oh, so much to learn and oh so fun!
Thanks again!