DC-Load wanted(Siglent SDL1020X-E found) - Page 1
Forum section: electronics / testgear

author: Martin72
author_rank: Super Contributor
timestamp: December 29, 2023, 11:49:31 pm
content: Edit: Title changedHi folks,I have almost everything a "private laboratory" needs, except for a spectrum analyzer and - loads...I would like to change that first before I buy an SA.First a DC load, I still have to think about AC, maybe I'll build it myself.So DC load... Which one...I would like to have one that I can regulate precisely to the mA, so that if I set a 5mA load, for example, it stays that way.Then I should also be able to make load jumps with it to test control loops.Furthermore, it should not interfere too much in order to be able to make reasonable ripple measurements.Maximum current...Hm...Let's say 20A, more if you like.Voltage 50V, also more if you like.Price...Doesn't necessarily have to be the cheapest, but as cheap as possible under the conditions mentioned above, just the usual.Make suggestions, I don't care about the brand.Oh yes, and sensible connections would not be bad, preferably terminals where you can also connect 4mm bananas.Thx in advance,Martin

author: blackdog
author_rank: Frequent Contributor
timestamp: December 30, 2023, 12:38:42 pm
content: Hi Martin,It is difficult to find a "Dynamic Load" that can handle small currents and e.g. 40-Ampere properly.It's a bit like with LAB power supplies you need several for certain applications.Often you want to work with small currents and rapidly varying loads like microcontrollers and i.o.t devices.So you want a good fast response, the dynamic loads that can handle large currents usually have an RC combination across the output terminals, because of this the peformance at smaller currents is not as good anymore since the low impedance vnadit RC network.Maybe build something yourself where you can control some properties yourself?For some inspiration take a look at this topic of mine on a Dutch forumfor a small fast active load.https://www.circuitsonline.net/forum/view/121338/1And a nother onehttps://www.circuitsonline.net/forum/view/106770/1And one specialhttps://www.circuitsonline.net/forum/view/153438Have fun!Kind regards,Bram

author: Martin72
author_rank: Super Contributor
timestamp: December 30, 2023, 01:51:14 pm
content: Hi Bram,Very nice...Must diving deeper into it, thanks for the links.The topic came up because I realized yesterday that I don't actually have any electrical loads here, except for something really bad from the China man.In my test field we have umpteen loads from "Zentro", as well as two from Rigol, which a developer colleague once bought for a project.I had a brief look at them, you can set the risetime there, which I found interesting, but the operation itself is terrible.Then we now have loads from Statron, for DC and AC, whereby the AC load is pretty cool:You do have a fine pot to slowly ramp up the load, but when you turn that, it clicks inside- It switches real resistors.I think I'm going to have to go in two directions, one for larger flows and one for smaller and more dynamic flows.As I said, I'll take a closer look at your design*, don't be surprised if I report on it in this thread, because that's when I started to rebuild it.Martin*(A few years ago I built myself a small load with several inputs because the test object had several outputs.Quite simple with an OP amp and "afterburner".The set currents always drifted away, so it ended up in the trash instead of thinking about why.)

author: tszaboo
author_rank: Super Contributor
timestamp: December 30, 2023, 04:12:11 pm
content: Does the Keithley DC Electronic Load Series 2380 fit the budget? I have that at work, nice unit. Also tests batteries. For anything complicated, more than two current levels, you need to script it though.I plan to buy a Riglol DL3000 at home, no experience with it yet. The base price is attractive.

author: Martin72
author_rank: Super Contributor
timestamp: December 30, 2023, 04:21:54 pm
content: Hi,Quote3300€.....No.QuoteMaybe it's also something for me, for larger loads.As I mentioned, we have two of them at work, I'd have to take a closer look at how they work and if you want to know anything specific about them, I can test them.

author: Grandchuck
author_rank: Super Contributor
timestamp: December 30, 2023, 08:06:58 pm
content: Hi Martin.The photo shows 10 minute drift anter 30 minutes warm up.

author: Warhawk
author_rank: Frequent Contributor
timestamp: December 30, 2023, 08:21:08 pm
content: Martin, I went for Korad KEL102 from Reichelt. Yes, it is Chinesium but surprisingly reasonable quality.It is a good all-rounder. I like LAN and the standard LCD. Upgrade when you need to. DC loads are annoyingly expensive.

author: Grandchuck
author_rank: Super Contributor
timestamp: December 30, 2023, 09:35:04 pm
content: After over an hour, still drifting up.Photo looks better too!

author: tszaboo
author_rank: Super Contributor
timestamp: December 30, 2023, 09:46:01 pm
content: Quote from: Martin72 on December 30, 2023, 04:21:54 pmI think I know what you mean. There is a lack of ~32V, 10A capable DC loads, that would come with a front banana jack. Only C brands seem to do this. But writing this, I just remembered, Itech has DC loads, the IT8211 would fit your basic specs. I don't have any experience with the brand, but they come up a lot in discussions. This one, I don't see any digital interface on it.

author: Veteran68
author_rank: Frequent Contributor
timestamp: December 30, 2023, 09:56:56 pm
content: Being somewhat of a Siglent fan, I'm surprised you've not mentioned the SDL series.The SDL1020X-E can be easily "upgraded" to the SDL1030X with 0.1mV/mA resolution and 300W max power. 5A/3A and 36V/150V ranges, configurable slew rates, battery test mode...Also the binding post knobs are easily swapped out for 6mm banana-capable binding posts from Aliexpress (the easiest/cleanest way) or via Clough42's PCB mod that keeps the stock knobs while adding banana jacks.

author: Martin72
author_rank: Super Contributor
timestamp: December 30, 2023, 10:54:42 pm
content: QuoteI´m not a Siglent fan.Siglent makes good stuff for the money, that's why I have some of it.But you can't do everything well, I don't know what they're like in terms of supplies and loads.But yes, the SDL would also be something, especially as it seems quite cheap.I think I'll buy a ready-made load and rebuild Blackdog's project, I'm currently designing a circuit board for it.I'll have a look at the loads mentioned, thanks for the input so far.

author: s54mtb
author_rank: Newbie
timestamp: December 31, 2023, 12:26:10 am
content: How about KEL2000 series?https://eleshop.eu/korad-kel2040-electronic-load.html

author: nctnico
author_rank: Super Contributor
timestamp: December 31, 2023, 02:31:32 am
content: Quote from: s54mtb on December 31, 2023, 12:26:10 amThese are quite good (the KEL2010 would fit Martin's requirements) after you move the transformer away from the analog control section. Still, single digit mA accuracy is getting into SMU territory.Some test data can be found here:https://www.eevblog.com/forum/testgear/korad-kel2010-multicomp-mp710771-review/msg4975759/

author: Martin72
author_rank: Super Contributor
timestamp: January 01, 2024, 01:25:49 am
content: OK,These three are currently being debated:Strictly speaking, the smallest Korad is dropped, leaving the second Korad and the Siglent(1020X-E).According to nctnico's report, I would have to tinker with the Korad to improve it, which somehow doesn't suit me.I don't know what to expect with the siglent, but I could easily get it and send it back relatively easily if I don't like it.I would test it like nctnico did with his Korad.

author: roy_eedreku
author_rank: Contributor
timestamp: January 01, 2024, 02:33:08 am
content: I had a KEL-103. I liked it for the couple of days that it worked but it just stopped working out of nowhere. The input terminals got shorted and I have no idea how. I was fortunately still in the return window so I didn't tear down or do further investigation. I do have the Siglent SDL 1020X-E right now and it is a great load! I have tested it with my power supply and I was able to accurately pull currents up to 1 mA. I didn't do it for long though so I am not sure about the drift.

author: nctnico
author_rank: Super Contributor
timestamp: January 01, 2024, 03:26:09 am
content: Quote from: Martin72 on January 01, 2024, 01:25:49 amJudging from a teardown of the Siglent load, it looks like the mains transformer is also relatively close to the analog control circuitry. But in the Siglent load the transformer is rotated by 90 degrees compared to the Korad load which could be better or worse. All in all it would be very interesting to see whether Siglent has a better design to deal with the magnetic field coming from the transformer.BTW: Tony Albus has created a video showing the Korad, Rigol and Siglent DC loads:

author: ArdWar
author_rank: Frequent Contributor
timestamp: January 01, 2024, 12:32:13 pm
content: I was taken aback by how deceptively hard it is to pick a good DC load.I once thought that KS EL34243A fits my requirement to a tee. Half rack, dual channel, fast digitization, fast arb waveform, LXI, institutional purchase so no problem with their BS cust support... Yet the only "review" here is basically a trainwreck (for $5K instrument). I wonder if it is still that bad.

author: Martin72
author_rank: Super Contributor
timestamp: January 01, 2024, 12:39:49 pm
content: QuoteThe Korad is "huge", so that could also be a criterion.From what I can see, and also from your report, it seems to be amazingly well made for the money and the terminals are everything you could wish for.Korad, you have to remember...I have now ordered the Siglent load, should arrive later this week.I'll report my impressions and tests here, I've also "heard" that you can "convert" the 1020X-E to a 1030X, which would be interesting in terms of resolution.But that would only be an issue if I liked the load, otherwise it would go back.At the same time, the self-build load will be pursued further.Edit:QuoteOh yes.And "good" also means the ease of use, how easy it is to set the desired settings.That's why the two new Rigol loads are in our cupboard gathering dust, while every colleague uses the ancient Zentro loads because they only have 3 switches and two pots...

author: nctnico
author_rank: Super Contributor
timestamp: January 01, 2024, 04:26:43 pm
content: Quote from: Martin72 on January 01, 2024, 12:39:49 pmI doubt that is truly possible as the 1030X lists a better accuracy compared to the 1020X-E. Unless the accuracy is crippled on purpose, there must be better parts used in a real 1030X.QuoteSkip the Rigols I'd say if that is the case. I have an older TDI DC load (1500W) which has a potmeter to adjust the current but the metering is not very accurate and you never really know where the pot is set to until you turn the load on. At some point I like to replace that one as well but I'm not sure I'd go for a Korad. But then again, it is hard to come up with an alternative that has good performance while being surprisingly cheap.

author: Veteran68
author_rank: Frequent Contributor
timestamp: January 01, 2024, 04:31:16 pm
content: I expect you'll be reasonably happy with the Siglent. It's not perfect, but what is? And yes, it's trivially easy to convert to a 1030X with 3 SCPI commands.Quote from: Martin72 on December 30, 2023, 10:54:42 pmTo be clear, when I said "fan" I meant someone who used and seemed to like their products. I was not suggesting you were an irrational fanboy, LOL.I myself am a Siglent fan in that I own several of their devices (scope, DMM, power supply, load), but I'm also a fan (so far) of my Rigol DHO1074 despite its rough edges -- at the price I paid, how could I not be? As long as it continues to serve my needs, I'll remain a fan. When it doesn't, I'll get something else. I'm certainly curious to see how the SDS1000HD plays out in the West.Quote from: nctnico on January 01, 2024, 04:26:43 pmWhy would you think it not possible? It's been done to death for years now. Of course theaccuracyresolution is crippled on purpose, same as with many of these instruments from Siglent, Rigol, and others. There is no hardware difference between them that I know of.EDIT: You said accuracy, while I meant resolution. Still not aware of any difference between these.

author: Martin72
author_rank: Super Contributor
timestamp: January 01, 2024, 05:16:19 pm
content: After comparing the specs it´s only themeasure resolution, nothing else.And more power...Maybe.And with simple using three commands I could turn the cheapest 1020X-E(522€) into the most expensive 1030X model(1177€).Sounds too good...Let´s check this before/after "tuning".This time I ordered from welectron, I know the discount coupon by heart and it was also valid for this load.So it is still just under 500(incl.VAT).

author: electr_peter
author_rank: Unknown
timestamp: January 01, 2024, 06:56:39 pm
content: FWIW, Rigol DL3000 electronic load series can also be modified easily (all models have the same HW) to get more power and resolution (color as well), instructions heredl3021-to-dl3031-conversion-discussionHowever, I would not recommend Rigol load to OP based on requirements, because old FW with bugs has not been updated for very long time.

author: Veteran68
author_rank: Frequent Contributor
timestamp: January 01, 2024, 09:38:28 pm
content: Quote from: Martin72 on January 01, 2024, 05:16:19 pmYes, the only difference between the two models is resolution and power. There is no “maybe” as to the power upgrade, it definitely works to upgrade to 300W. I’ve done the upgrade to mine, and there are numerous videos of the upgrade being tested.

author: Martin72
author_rank: Super Contributor
timestamp: January 01, 2024, 10:53:29 pm
content: Quote from: Veteran68 on January 01, 2024, 09:38:28 pmThere is still the possibility that the hack only shifted the power limit upwards, or are there pictures of the inside of the 1020/1030 where you can see that it has the same hardware design?

author: Veteran68
author_rank: Frequent Contributor
timestamp: January 02, 2024, 01:44:02 am
content: Quote from: Martin72 on January 01, 2024, 10:53:29 pmI can't point to any photos offhand, but I've seen and read that they're the same. Many have done the upgrade and I've seen reports of tests to 300W.And there'sthis post, although not accompanied by any photos, so you'd have to take their word for it (unless there's later photos, I haven't read the entire thread).Quote from: Elasia on May 15, 2020, 05:52:09 pm

author: nctnico
author_rank: Super Contributor
timestamp: January 02, 2024, 02:40:37 am
content: Quote from: Veteran68 on January 01, 2024, 04:31:16 pmCheck the datasheet really carefully and you'll see there are differences in the accuracy specifications between the models.And even though the board may look the same, it is possible the higher end models use more precise versions of the same components. Look at the LM4040 voltage reference as a random example. It is available in 4 grades going from 0.1% to 1%.

author: Martin72
author_rank: Super Contributor
timestamp: January 02, 2024, 07:21:12 am
content: In all the values listed in the data sheet, there are only differences in this area ("Measuring Range") between the more expensive X model and the cheaper X-E variant.However, I am not yet able to clearly assign the term "measuring range".It can mean that the measurement and display are more accurate, but it can also mean that the better accuracy is not only used for display purposes, but is included in the overall accuracy.As I write this, I think the latter will be the case.

author: nctnico
author_rank: Super Contributor
timestamp: January 02, 2024, 07:50:06 am
content: Look at the accuracy specs. I never wrote about resolution

author: Martin72
author_rank: Super Contributor
timestamp: January 02, 2024, 12:19:33 pm
content: Ah, ahh...I didn't see that...Well, the only solution would be to actually and directly compare an X model with an X-E via teardown.Or, I would take and save various measurements, then "optimize" and repeat the measurements.What I find suspicious is this jump in price.However, if you can convert a Siglent 2.1Ghz SA to a 3.2Ghz SA/VNA, why should it be any different in the case of loads?The only way to find out is to test more thoroughly.

author: egonotto
author_rank: Super Contributor
timestamp: January 02, 2024, 03:00:27 pm
content: Hallo,The accuracy figures for readback voltage are somewhat strange. Since the X-E model has only 0.02% at FS, while the X-Model has 0.025% and thus less accurate in this range.Best regardsegonotto

author: delvo
author_rank: Contributor
timestamp: January 02, 2024, 03:18:04 pm
content: One downside to the siglent ones is that there is no public calibration/adjustment procedure (Id love to be proven wrong on this)

author: Martin72
author_rank: Super Contributor
timestamp: January 02, 2024, 03:26:09 pm
content: We (at work) had this topic in general a few years ago, regarding power supplies/loads also calibrating (having them calibrated).If you record/measure the voltages/currents with external (calibrated) measuring equipment anyway, then you don't need to have it calibrated.

author: alm
author_rank: Super Contributor
timestamp: January 02, 2024, 04:00:59 pm
content: Quote from: Martin72 on January 02, 2024, 03:26:09 pmSure, but isn't the value in a modern load / power supply the built-in measurement and programming features? Otherwise you could also use an old load or power supply with analog panel meters. You could of course do a software correction yourself before programming / after readback, so if you want it to sink 1 A and you know it's 1% low, you tell it to sink 1.01A. And if you know it reads back 1% high and it reads 1.01A, you calculate this to be 1A. But this is a hassle.I don't understand the trend of particularly the upcoming brands like Siglent to not publish adjustment information. It's not like adjusting a power supply or electronic load is difficult or requires special equipment. A good DMM with an external current shunt for higher currents should be sufficient for 95% of the adjustments. The only exception would probably be rise time tests which would require a scope.

author: Martin72
author_rank: Super Contributor
timestamp: January 02, 2024, 04:05:40 pm
content: QuoteThat's another question, whether you have to have a flowing current of 1A with an accuracy of less than 10mA.Nevertheless, I can try to get more detailed information, which I would then share accordingly.

author: Martin72
author_rank: Super Contributor
timestamp: January 03, 2024, 12:17:18 am
content: Quote from: blackdog on December 30, 2023, 12:38:42 pmHi Bram,In progress...Martin

author: orzel
author_rank: Regular Contributor
timestamp: January 03, 2024, 01:16:19 am
content: Quote from: Martin72 on January 03, 2024, 12:17:18 amWhat a teasing !

author: nctnico
author_rank: Super Contributor
timestamp: January 03, 2024, 05:50:57 am
content: I'd put the opamp much closer to the transistors and make sure high impedance nets (especially the feedback loop) have the smallest possible loop area.

author: Martin72
author_rank: Super Contributor
timestamp: January 03, 2024, 06:07:16 am
content: Good hint, I´ll place a part of the circuitry on the bottom side.

author: nctnico
author_rank: Super Contributor
timestamp: January 03, 2024, 01:15:00 pm
content: Quote from: Martin72 on January 02, 2024, 12:19:33 pmYou can't really test it. You need to identify the components that determine the accuracy. But even if the sample of the lesser model you have has the higher spec components, you can't be sure a lesser model always has the better components in them. Old story from S.E.D.: One of the members over there produced a circuit that needed 1% capacitors. But since these where expensive, they bought the 5% ones and binned them. The excess capacitors where used elsewhere, so nothing got wasted. However, one day they received a batch where all the capacitors within 1% tolerance where missing. In the end you can't be sure unless you specifically buy a part of piece of equipment that is specified to certain accuracy / tolerance levels.

author: Martin72
author_rank: Super Contributor
timestamp: January 03, 2024, 01:56:00 pm
content: Hi,QuoteIn this case, I wouldn't care if another batch was equipped differently.I have the "good" one.But I know what you mean and how you mean it.The load is already on its way, I can test it at the weekend.

author: Martin72
author_rank: Super Contributor
timestamp: January 03, 2024, 02:48:56 pm
content: QuoteMust correct this...Let it acclimatise first...

author: 5U4GB
author_rank: Super Contributor
timestamp: January 04, 2024, 01:39:54 am
content: A vaguely-related question, I know the OP asked for mA-level loads but for general-purpose low-voltage testing are the Chinesium ones that bad? I've got one of the near-infinite number of copies that consist mostly of an Intel-style CPU heatsink and fan strapped onto the load FET, but with the great feature that it has every style of USB connector in existence, as well as barrel jacks and screw terminals, which means I can do immediate no-hassle testing of 5V/12V power supplies, cables, and whatnot to diagnose power problems with various devices, and accessories like solar panels used to drive some of said devices, for example to check whether the claimed 5W panel really is 5W (no, it's 0.75W). I wouldn't use it for precise testing, but for sheer convenience it's hard to beat.

author: orzel
author_rank: Regular Contributor
timestamp: January 04, 2024, 02:40:40 am
content: What you describe definitely sounds like an "Atorch DL24". I got one, and I find it very useful as a "better than nothing" electronic load. I got a 180W model and I use it up to 150W very often, and it hasn't burnt yet. Though some other people were less lucky it seems.Of course it's not a proper/genuine electronic load, it's not even sold as is (it's officially a "battery tester"). But still, for the price, I'm very happy so far. I got a version with bluetooth, but it's buggy like hell and I don't use it.Obviously, I don't design power supplies, so my needs are very modest.

author: 5U4GB
author_rank: Super Contributor
timestamp: January 04, 2024, 09:27:00 am
content: Yup, it's from that general family, I just got one with coarse and fine pots rather than the pushbutton one which makes it easier to vary the load slightly over time, but that's just a personal preference. As with your use case, it does what I need even if it's not terribly fancy and it's incredibly convenient to have all the required connectors built in.

author: blackdog
author_rank: Frequent Contributor
timestamp: January 04, 2024, 07:43:20 pm
content: Hi,To make things a little clearer here is the diagram Martin72 is talking about..The BNC connector attached to R1 is the DC input, which allows you to set the DC current via e.g. a LAP Powersupply, DAC, 9V battery.The BNC connector below it can be used with a function generator that gives you a negative DC signal modulated with an AC signal.A combination of both inputs is also possible, it's your party. :-)Keep in mind the eventual interaction and the large RC time of C1 of 47uF.If you don't want to modulate at low frequencies, you can also make this capacitor C1 4.7uf, adjust for what makes sense for you.I added a Stand By switch and that is S2, if the contact is made then the -input of the NE5534a is pulled to the positive power supply by the orange or the red LED depending on the function.With large signals on the inputs maybe R11 of 6K8 is not good enough, make it 3K3 or so.The 80C Clikson take from a temperature value that fits your cooling element for the MOSFets and the power you want to dissipate.I have good results with the modern PC Processor coolers, mount the MOSFets directly on the cooling element and mount the cooling element isolated in the case.This gives the best cooling for your MOSFets.I have tried to squeeze as much performance out of this circuit as possible and that the circuit also still maintains good stability.But there are plenty of "tune" possibilities to experiment with.The limitations are mainly in the speed, that is the speed of the NE5534a, the compensation by means of C7 of 560pF and the Drain/Gate capacities at a large AC swing on the Drains.Not every load is a power supply with a good capacitor across its output terminals.I also tested this Dynamic Load with a 4 Ohm and an 8 Ohm resistor without Snubber circuitry.And taking that into account, I determined C7 to be 560pF.But you can still test some faster Power Supply's, and then there are several possibilities.Use the input that R1 is connected to, it does not have a 100Khz low pass filter.And second, use the normal modulation input through C1 and then make C7 smaller but not lower than 180pF.Otherwise the phase margin becomes too small and you could sometimes get generation problems.The purpose of C3 of 330pF is, to not feed the NE5534a too fast edges that it cannot handle.As a tip, don't go too far with boosting the speed.This circuit is intended for my normal wiring length of about 30cm between the Dynamic Load and the D.U.T.And of course twist the wires, about 1 twist per Inch is OK.This then still results in a paracitic inductance, that if this inductance is driven too fast by steep edge from the Dynamic Load can produce resonance.How do you measure the properties of e.g. a linear power Supply.I use the following signal for this purpose, 400Hz with 10% Duty Cycle.The slopes are then 50 to 1uSec this depends on my application.The minimum current I draw is then 10% of the maximum current of the Power Supply and the maximum current is 95 to 100%.I use a battery scope to measure the error signal on the power supply terminals.Clean your banana plug sockets just like your banana plugs with e.g. IPA!And I don't mean beer by that! :-)Connect the scope via a coax cable to the + and - connection, so e.g. the holes for wire connection in the banana plugs.And connect de Dynamic Load via Banana plugs.Don't use banana plugs you can stack! WRONG!Or actually do it once the right way as I describe and then once the wrong way which you can see a lot via Youtube, they really know what they are doing :-) and see the difference on the scoop.A different and verry fast Dynamic LoadFor very fast test pulses, I use a circuit by Jim Williams that was in one of his Application Notes.Then I do not use a connecting cable but use an almost direct connection via a bannaan coupler, this is to keep the inductance as low as possible.Then I can test up to 1MHz block pulse, but every mm of wire already gives abberations on the signal to be measured.So increasing the speed comes with al kind of different limitations and it is good to learn and realize this. :-)I designed this circuit about 10 years ago, now I would do some experimentation with MOSFets that have smaller internal paracitic capacitances and are also suitable for linear operation.But I still think this circuit is suitable for the hobbyist to have fun experimenting with and get good results.Oh well, I chose the NE5534a specifically for this application!Low Noise and sufficient output current with reasonably good bandwidth and it costs little.And the offset is the trim and it remains reasonably stable.So do not think I put in a uA741 , TL071, LM324, no, no,no. :-)With kind regards,BramTranslated with DeepL.com (free version) <= So I hope you will take that and my dyslexia into account.PSSome test picturesThis is the current pulse measured at the BNC output, that is, the voltage across the Source resistors from a measurement at a linear HP6237A power Supply.The Dynamic Load draws a clean pulse from the Power Supply under test, no abberations are visible.(twisted pair wiring used).The maximum current is slightly above the maximum current the Power Supply can deliver, this is possible due to the energy contained in the capacitor across the output terminals of the Power Supply.By making the current pulse even larger or making the duty cycle longer you can gain insight about the current behavior of your D.U.T..This photo shows the result of the current pulse used.This is the voltage across the output terminals of the HP Power Supply.The Phase Margin and Gain margin of this power Supply is optimally set, by the way, this is the 18V output that can deliver a maximum of 1-Ampere.If the pulse drawn by the Dynamic Load becomes even faster, then the peak amplitude will become even higher.The reason is largely the inductance of the capacitor across the output terminals and the measurement point of the scope.I usually mount my measurement cable on the back of the banana terminals to avoid suffering from the inductance of the connection terminals.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: January 04, 2024, 07:54:39 pm
content: If you're on a budget, this is hard to beat price-wise.https://vi.aliexpress.com/item/1005005997230178.html?spm=a2g0o.order_list.order_list_main.5.3ac21802x8cQJa&gatewayAdapt=glo2vnmI've only given it a cursory test so far but seems to basically work. rate of change of load is quite heavily damped so probably no good for impulse/load-step testing.

author: Martin72
author_rank: Super Contributor
timestamp: January 07, 2024, 06:47:32 pm
content: I haven't really tested the siglent yet, but I couldn't contain my curiosity and unscrewed it earlier.The clean build quality is very good, nothing to complain about.12 IRFP250 FETs do their job there, which should easily be enough to turn the 200W load into a 300W one.A very small detail also convinced me that the "hack" should not cause any major problems...

author: Martin72
author_rank: Super Contributor
timestamp: January 13, 2024, 11:04:12 pm
content: After I quickly and successfully "upgraded" the load to a1030X, it's time to test it too.However, something came up in between (testing the Micsig CP1003 B), but I'll soon get started.I will stick to what nctnico tested, it seems to make the most sense to me.And today the boards for the DIY load arrived, still with the "old version" of my load board, where they had (rightly) criticized the too long feedback paths.But it was already in production and that's why it's here now.The temptation is there to fit both revisions and test whether and what difference this makes in practice.I will soon have completed the design for the new revision.Martin

author: oz2cpu
author_rank: Frequent Contributor
timestamp: March 09, 2024, 02:21:52 pm
content: about siglent SDL 1020did anyone figure out the internal programming modes ?like you can make a lot of steps that do any type of mode and feature, and delays and all that,BUT i am missing a REPEAT or LOOP or goto x step feature ??the program only run once, and that is far from what i need,I can ofcourse use a pc to control it, but such simply thing as a loop feature must be there , right ??forgot to say the DC supplies from siglent wich i also own, dont have loop feature in their internal programming either..SOLVED : dont use PROGRAM no loop feature to find there..use the less obvious LIST in here you make a list of settings, and the repeat number can go below 1if you dial it down there, it will go on forever

author: 5U4GB
author_rank: Super Contributor
timestamp: March 25, 2024, 07:20:19 am
content: Quote from: orzel on January 04, 2024, 02:40:40 amI may have discovered why, I wanted to measure noise from a random SMPS at different power levels and decided to use one of these to do it. The result was waaay noisier than even a relatively crappy SMPS should be, while a resistor kludge load didn't exhibit the problem. I haven't looked at the loa... battery tester in any detail but it's possible it's using PWM control from the micro that runs it, or at least doing something that makes it impossible to get a reliable noise reading.

author: 5U4GB
author_rank: Super Contributor
timestamp: April 20, 2024, 12:01:08 pm
content: Just a caveat for anyone using the CPU-heatsink+fan-combo devices from Aliexpress, these things are noisy as FiretrUCK. I knew that they were a bit problematic and was using a resistor+fan bodge instead for PSU noise measurements but didn't realise just how bad they really are until I had to get measurements for something where I didn't have the right resistor values/power levels and pressed this into service. No matter what I did I couldn't get useful readings despite being in an environment set up to minimise noise, until I ran it with a decent-quality low-noise linear power supply. Here's the result at 250mA:Here it is at 1A:So they're fine for battery capacity testing, which is what they seem to be aimed at, and fine for checking for voltage stability at various power levels, but no good if you're wanting to make noise measurements at different power levels because most of the noise you'll be seeing will be created by the load.Now I need to decide whether I want to get a bunch of additional wirewound resistors to measure other voltages at set current levels, or cave in and buy a proper electronic load. I mean, we all know how this isgoing to end, but I'd like to at least maintain the pretence that I have options.