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Power supply for home lab - do I really need a R&S?

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moerm:

--- Quote from: FranciscogGomez on May 11, 2024, 05:38:36 pm ---... I overlooked this important specification from it

--- End quote ---

Not only that one...

[quote author=FranciscogGomez link=topic=427153.msg5494642#msg5494642 ey pdenisowski,
For the price of a NGE103b, I can get a mid-quality but decent power supply (that will do its job) for less money; which will leave my wallet with  extra cash to get more equipment.
Regards
[/quote]

How to provide advice when your requirements a bit all over the place, meager, and "floating"?

Based on what I seem to have understood as your requirements I'd pick the Siglent X (not X-E) out of those you listed. Simple reason: Not known for having significant flaws, specs seeming to meet your requirements and at about half the cost of the R&S one.
Explanatory note: I consider Siglent to be a chinese "halfway A class" brand that is, I wouldn't (yet) put them next to western A brands like R&S. BUT: I guess we've all seen quite a few cases of A brands selling mediocre or somewhat flawed products.
All in all I look at Siglent as a brand with, for China, good engineering and build quality, certainly good enough for a hobby or (not high-end) lab with a, for China, matching price that is, usually not among the cheapest chinese instruments but still significantly cheaper than comparable western brands.

Side note: I (but that may be a personal thing) would absolutely not buy a multi-channel PSU without properly and fully independent/separate channels. I didn't check that yet for the Siglent PSU but definitely advise you to check that.

Finally, yes, there are quite a few excellent western (good) brand PSUs which are within $ reach for you. Their main advantage IMO is that they are "battle-proved" and most of them are very well known here, have been torn down and analyzed, etc. and also often have schematics available. Their disadvantage is that buying second hand, e.g. from ebay, always carries some risk unless you buy from a very well reputed seller.
All in all I personally would go that route (old, second hand) but one thing I'd certainly *not* consider: to buy a R&S PSU with a known, and known since years yet still not fixed (AFAIK) significant flaw. A Siglent PSU that meets my requirements I would, however, consider.

thm_w:
Here is rigol dp932:


edit: older R&S PSU I have also has a similar issue, but not as bad.

mawyatt:

--- Quote from: nctnico on October 02, 2024, 08:27:40 pm ---I think the control loop is in software though. I have an Agilent 66311B which has the same 'problem' (delayed current limit). If the current limit is done in an analog circuit, then I don't see how you can screw up a power supply circuit that bad. OTOH, it could be done to deal with circuits which have a rush-in current which otherwise wouldn't start up properly. Some DC-DC converter modules are prone to not starting when the current limit is set too low. But I can't see this as a good point on a general purpose lab PSU though.

--- End quote ---

There are "certain" applications like motor startup, SMPS startup, and so on that require a significant startup current but this high current at Turn On shouldn't be "built-in" to the basic PS as a default setup parameter. This should be a user settable parameter either by a panel switch (old school) or modern UI Input.

Remember long ago when a Power Designs (think this was the type) PS had a Turn Off glitch that cost us  a couple $50K custom chip sets. When discovered we immediately took a hammer to the PS and returned it the "Calibration Dept" ;)

In Power Designs defense (or whoever it was), this wasn't a design defect, but a component failure, as we had many of these supplies in our lab and checked every one after this incident!!

Best

mhsprang:
The behaviour of the CC mode is even worse than I imagined. I did the following test: set the voltage to 8V, current to 10 mA, load is 50 Ohm. Image Scope_1 shows the transient when I hit the Output button on the NGE100. The first peak is almost 7.5V, so the current is appr. 150 mA. Then it remains stable at 120 mA for over 30 ms and then it decays to 20 mA (1V over 50 Ohm).

Measured over a longer period, see image Scope_0, the current decays almost linear to 10 mA. This takes a whopping 12 seconds!!

And finally, I attached a LED to the power supply. To no surprise, the LED did not survive.

I will send all of this to R&S and see what they have to say. This behaviour is unacceptable for a reputable brand as R&S.
@Anyone from R&S on this forum: feel free to comment...

mhsprang:
Just for "fun", I set the Ramp time of the output to 0.1 s. That didn't help either.

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