Bench Power Supply Testing, Homemade vs. Korad KA3005 vs. LongWei LW-K3010D
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- čas přidán 13. 01. 2020
- In this video I'll be testing and comparing 3 power supplies, my homemade dual rail, the Korad KA3005 and the LongWei LW-K3010D.
This tests performed are:
- Peak short circuit current while current limited
- Output Impedance
- Behavior with dynamic load, CV + CV going into CC. - Věda a technologie
The SMPS based bench supply has a long wei to go.
lol.. very good
Thank you for sharing your knowledge for us who are still learning what you share would take so long to learn by ourselves.
Thanks, I'm happy you enjoyed the video.
Thanks for the video. I'm just getting into the hobby and have been on the fence about the Korad power supply you tested, but now have it on my list.
It's a good power supply, I can recommend it.
Cheers,
Jake
Helpful tests. Thank you!
Very interesting tests.
Thank you!
Thanks!
Very good. Learned a lot. Thank you very much.
Great work on the tests!
Thanks!
Best information 👌 on Bench power supply..very helpful 👏
Thanks, good to hear you found it useful.
Cheers,
Jake
Great video
Thanks
great.... we try noise in,,,, noise out tests too
Very nice and interesting advanced-level performance tests you performed on those PS units. At 9:16 I tend to disagree your statement: mid and high-end power supplies (including your Korad one) have the possibility to preset the voltage & current settings and they have an output on/off switch. If you use that built-in switch, it will not overshoot in cc mode. By using your external opamp-mosfet switch, you compromised the performance you were expecting for. I know for sure because I tried both ways with my TTi PL-601 unit and saw the difference.
Hi paulbt, thanks. I agree with you about the power up current limiting, however the scenario I'm testing here is how much current the supply will deliver once it's already up to the set voltage and then the output is shorted. A realistic scenario would be if you have a circuit powered up on the bench and you are probing some pins with a scope or multimeter and accidentally short one of them to ground or the positive supply.
Cheers,
Jake
@@TheStuffMade yep, you are right then, I never thought about this scenario. In this case the amount of output capacitance does matter and also the response time of the feedback loop that is regulating the output. Regards!
Excellent video very easy on the ear, many thanks. Can you tell me the video you did and the mod to stop the on switch spike and where to fit output capacitor for prevention. I have a 30v 10A similar PS and blew mosfet when setting amperage my fault voltage and amps were to high when I shorted the leads. Thanks again.
Thanks, I have a video where I make a few simple modifications to get rid of the switching noise:
czcams.com/video/WytDROmjWKQ/video.html
Cheers,
Jake
Not surprised the Home Made one (capitals intended) exceeded both of them by a few miles.
A good example of "horses for courses" - All power supplies are not born equal. If you are playing with low noise op amp circuits, build yourself a linear dual rail supply. If you are building a 500W fairground lighting controller , go with a smps!
Yeah, that's a really good way to put it, we need all the different types of power supplies, each with their own strengths and weaknesses.
Cheers,
Jake
Is not it possible to build a circuit that when current limiter reach's Max set current it shortens the output capacitor ( with "output enable/disable discharging" switch )?
Yes, for that to work the design will need to have a shunt after the capacitor on the output to measure the actual current and then use a feedback loop with a transistor to discharge the capacitor when the current is too high.
Why you wanna do that ?
It swithes off right ?which It should do .
I guess the discharging Will reduce the voltage if that maybe a problem ? ?
Buy that may up the current again ?
I may be totally wrong ,Just asking
Very informative. I have the same long wei supply and it is indeed very slow in regulating current. I did blow some fuses due to this supply 🙄
Thanks, yeah, have to be a bit careful with the LongWei, but it's still great to have around when you need a lot of current. I have another video on this power supply where I make a small mod to get rid of the switching noise issues if you are interested.
Cheers,
Jake
@@TheStuffMade I'll attempt to do that mod. That video was very detailed and well explained too. 👌👍
Great video. Can you share the schematic for the diy power supply? Thanks
Thanks, the download for schematic, gerber files etc are linked in the build video's description: czcams.com/video/jBtNH1EbU8M/video.html
Cheers,
Jake
Are you the guy that made a better impedance analyzer for the analog discovery?
Indeed, I designed and build mine long before Digilent came up with their version. You can download all the details (schematic, board layout, software, instructions etc) if you find my video on the latest version and check the download link in the description. Be aware the software might not run correctly for Analog Discovery 2, I've had some mixed reports, but I don't have an AD2 to test it.
@@TheStuffMade , did digilent incorporate your improvements, like calibration procedures?
@@hansjalbertsson7736 Not that I'm aware, however it's not really my invention how to calibrate an impedance analyzer, I got most of the theory from the HP/Agilent/Keysight Handbook on Impedance Measurements. It's an excellent compendium on impedance measurements and very much worth a read if you are interested in how it works.
@@TheStuffMade, of course you're not the inventor of calibration but you did include calibration procedures and gui elements in your sw! Which is more than good enough!
I suppose you can hand compensate an impedance measurement in Digilent's sw, if you measure enough well known components first?
@@hansjalbertsson7736 Sure I know math and I did work as a senior lead developer at Microsoft for a decade, however I have little interest in the Digilent software.
Any video in your channel to show how to make homemade psu?
Yes, the build video is here: czcams.com/video/jBtNH1EbU8M/video.html
Link in the description to download schematic and board layout etc.
so actually it is better to build our own power supply than buying cheap ones on AliExpress? (or pay 6000 $ for Rodhe and Schwarz)
Seeing this my old idea comes to mind: How about switchable capacitors for the output?
One low value, one high value.
Depending on what you do with it, you can choose between them.
I've seen one guy who straight away exchanged the 300ish μF cap on his power supply for a 47μF one, if I recall correctly.
(I am kind of binge watching lab psu stuff the recent days)
hey, can you tell me how to find the guy switching caps?
@@dany_2945 Sorry, but I watched so much other content in the mean time, I would not find that anymore.
I only recall him replacing the 300ish μF output cap with a 47μF one, so the charge and discharge time is lower. For his application it was fine, but you sacrifice a bit of voltage smoothing that way.
My Korad had famous crash issue even with the updated boards. I'm done with this Chinese junk. From now on, on keep on saving money to buy Rohde & Schwartz or similar high end equipment. Granted you can buy a complete lab with Owon or Siglent stuff for the price of just a Rohde & Schwartz power supply, but at least you don't have to worry about the equipment failing or, even worse, destroying anything hooked up to it.
Chinese just can't designing anything decent.
That's a shame your power supply broke down, however it's unlikely to be the same issue as the first revision boards. Why not have a go at repairing it? Keep in mind that all power supplies break down from time to time, including the most expensive ones from HP/Agilent/Keysight or Rohde & Schwartz.
Cheers,
Jake