Measuring power supply ripple with Siglent 1202X-E - Page 1
Forum section: electronics / testgear

author: MarioBros69
author_rank: Contributor
timestamp: August 31, 2023, 09:24:29 pm
content: Hello, I have tried to measure the ripple of a Geti 3005E power supply, according to the specifications the ripple should be 1mV (RMS) 20mV (p-p)The two pictures below are almost the same, but one is with the power supply on and the other is with the power supply offHow is this possible?The 1202X-E is not valid for measuring the ripple of this source or is it that the noise exceeds the ripple and I can't see it?" alt="" class="bbc_img" />" alt="" class="bbc_img" />

author: Grandchuck
author_rank: Super Contributor
timestamp: August 31, 2023, 09:29:20 pm
content: Noise from the environment. Not the power supply.

author: pope
author_rank: Frequent Contributor
timestamp: August 31, 2023, 09:31:53 pm
content: Better measure with the bandwidth set to 20MHz (not full as in your pictures)

author: Martin72
author_rank: Super Contributor
timestamp: August 31, 2023, 09:32:00 pm
content: Hi,First, real screenshots from the scope would be better.Then:What we see there is only noise, not ripple - Because the setup you made is not the way it should be.Ripple has to be measured as near as possible, so you should measure it directly at the output, to minimize unwanted noise.

author: MarioBros69
author_rank: Contributor
timestamp: August 31, 2023, 09:51:55 pm
content: The truth is that I have tried connecting the probe directly to the source and there is no big differenceWith 20 Mhz it removes some noise but I still can't see the ripple and the strangest thing is that with the source off it shows almost the sameWith this oscilloscope and the default probe, should I be able to see it?Below a closer shot

author: tautech
author_rank: Super Contributor
timestamp: August 31, 2023, 10:00:25 pm
content: Quote from: MarioBros69 on August 31, 2023, 09:51:55 pmIs the PSU loaded in any way ? It needs some otherwise noise makes measurements incorrect.BW limit and 1x probe should be used for PSU measurements.Also you need take screenshots to USB with the blue Print button. < much much smaller than photos and better detail.

author: MarioBros69
author_rank: Contributor
timestamp: August 31, 2023, 10:07:04 pm
content: I only had it for a few days to test it and my intention is to buy a 1104X-E but I was a little disappointed not to be able to measure the source rippleI seem to remember that I also tried x1 and with 20Mhz activated without a big difference" alt="" class="bbc_img" />

author: MarioBros69
author_rank: Contributor
timestamp: August 31, 2023, 10:11:27 pm
content: Quote from: tautech on August 31, 2023, 10:00:25 pmI seem to remember that I also tried x1 and with 20Mhz activated without a big differenceIn some of my tests I put a 1K resistor as a load, but in these photos it is not included

author: tautech
author_rank: Super Contributor
timestamp: August 31, 2023, 10:17:25 pm
content: Quote from: MarioBros69 on August 31, 2023, 10:11:27 pmFirstly, ~15us period indicates some 50kHz, is that expected ?Load the PSU more and check for local interference sources, wallwarts and such.Don't blame a sensitive scope for the noise, it's what's there !

author: Electro Fan
author_rank: Super Contributor
timestamp: August 31, 2023, 10:23:40 pm
content: These two videos will help you measure signals that can be sensitive to how your scope and ground connection are set up.If you want to see what the power supply really can do on the ripple measurement try using something like these:https://www.pomonaelectronics.com/products/adapters/bnc-f-double-stacking-banana-plughttps://www.mouser.com/ProductDetail/Cal-Test/CT3655?qs=vgjKjNJexTj1hwPidYnr1Q%3D%3DThey come in different sizes - make sure to get one that will fit the oscilloscope probe you are using.https://www.farnell.com/cad/2702874.pdfThis 3.5mm adapter fits a Rigol RP3300A. Some of the older Tektronix probes I think require a slightly larger adapter. Not sure what size your Siglent probe requires - tautech can probably help you determine that.

author: tautech
author_rank: Super Contributor
timestamp: August 31, 2023, 11:20:58 pm
content: Quote from: Electro Fan on August 31, 2023, 10:23:40 pmMario has a SDS1202X-E supplied with PP215 probesandprobe to BNC adapters.These are a nominal 5mm tipped probe and these should fit (select 5mm size)https://www.aliexpress.us/item/2255800926120810.html?

author: Caliaxy
author_rank: Frequent Contributor
timestamp: September 01, 2023, 12:00:22 am
content: Have you tried turning your (presumably LED or fluorescent…) lights off?

author: BillyO
author_rank: Super Contributor
timestamp: September 01, 2023, 12:51:55 am
content: Quote from: tautech on August 31, 2023, 10:00:25 pmWhy?This is one of those ancient things from a bygone era when the scopes got better than 20MHz BW but the equipment under test could not react to noise at higher frequencies. This is a different time and ignoring HF PS noise can lead you to endless grief.To the OP:Turn off your PS and measure the noise. See if any of that is being caused by something else.

author: tautech
author_rank: Super Contributor
timestamp: September 01, 2023, 03:15:27 am
content: Quote from: BillyO on September 01, 2023, 12:51:55 amI said:BW limitand 1x probeshould be used for PSU measurements.The modern 1x probe is itself a BW filter to some 6-10MHz as its additional tip capacitance helps reduce noise.Of course probing technique itself further determines what we might see as does if the PSU is linear or SMPS.The OP'sscreenshotsphotos indicate something at 50+kHz plus lots of other random noise, some of which is expected at higher sensitivity settings when probing technique is suboptimal.For his 20mV/div 10x probe setting the actual scope setting is 2mV/div and well within the region where all manner of noise gets displayed.His PSU appears linear with a ripple and noise CV <1mV rating so at these levels probing technique is everything so to not get bogus results and with us timebase settings instead of ms settings for a linear PSU it's no wonder the man is confused when using a highly sensitive scope with a fine antenna probe based measuring system.

author: MarioBros69
author_rank: Contributor
timestamp: September 01, 2023, 05:46:54 am
content: Thank you for your answers, when I receive another device I will put all your advice to the test, measure in X1 with 20Mhz and the source with a load and direct connection to the source terminalsThe power supply is linear and I have tried turning off all the LED lights, I have even taken the power supply and the oscilloscope to the kitchen and I got the same result, it is as if that noise were in the electrical grid and will be amplified within supply transformersThe strangest thing is that with the power supply off I get the same noise level

author: BillyO
author_rank: Super Contributor
timestamp: September 01, 2023, 05:50:36 am
content: Quote from: MarioBros69 on September 01, 2023, 05:46:54 amThat's where you need to start. Get that noise dealt with first.

author: tautech
author_rank: Super Contributor
timestamp: September 01, 2023, 07:00:01 am
content: Quote from: BillyO on September 01, 2023, 05:50:36 amYep, and it could be anywhere nearby.A customer with brand new 4ch X-E called, convinced the new scope we supplied was faulty as there was unexplained 24kHz interference in his circuits......a wallwart behind a curtain across the room was the culprit.

author: Kean
author_rank: Unknown
timestamp: September 01, 2023, 09:47:29 am
content: Quote from: tautech on September 01, 2023, 07:00:01 amAlways pay attention to the wallwart behind the curtain!

author: tautech
author_rank: Super Contributor
timestamp: September 01, 2023, 10:07:53 am
content: Quote from: Kean on September 01, 2023, 09:47:29 amIt had the poor chap really stumped after checking adjacent rooms and turning OFF most appliances in his house then to find a wallwart that belonged to whom he did not know.It's only when you purposely go looking for RFI with something as simple as the Reference (Gnd) lead clipped to a probe grabber which makes a useful RFI pickup that you realise how many appliances are noisy, either their circuits or PSU's.So useful is a probe used in this manner I even use it for setting peak RPM in a chainsaw.12000rpm/60 = 200Hz.

author: BillyO
author_rank: Super Contributor
timestamp: September 01, 2023, 04:52:10 pm
content: Quote from: tautech on September 01, 2023, 03:15:27 amAll agreed.My point though was to not use any kind of filtering. It just amounts to sweeping the dirt under the rug.

author: dophuc
author_rank: Contributor
timestamp: September 01, 2023, 05:48:30 pm
content: Here is how I tested the ripple & noise of DC power with Scope:- The DC power supply and the Scope are powered by an isolating transformer to ensure that they are not affected by AC mains. If I want to be more precise, I will separate the power supply for the oscilloscope from the AC mains, while the DUT is powered by an isolation transformer.- Coax cable attached to the Siglent SDS1104X-E.- At the output of the DC source, I connect 0.1uf+10uf (50V) ceramic capacitor in parallel, and use a 0.01uf capacitor to block the DC signal. I tried replacing the 10uf ceramic capacitor with a 10uf Tantalum capacitor but the results didn't make much of a difference.- Ripple & noise about 3.36 mVp-p.Compared to using probe with GND wire ripple & noise about 8.96 mVp-pAnother example compares the ripple & noise of 65W GaN charging when using the oscilloscope probe far from the source with using a coax cable near the output of the source, the results will be different.

author: markus_jlrb
author_rank: Regular Contributor
timestamp: September 02, 2023, 06:25:56 am
content: BTW,the KP18X introduce own noise,se threadhttps://www.eevblog.com/forum/testgear/an-investigation-about-ripple-current-of-kunkin-kp184/Take a plain resistor as load not to mix noise of other devices in your test.Markus

author: BillyO
author_rank: Super Contributor
timestamp: September 02, 2023, 06:43:23 am
content: Quote from: markus_jlrb on September 02, 2023, 06:25:56 amWell, that's the trick isn't it?

author: u666sa
author_rank: Frequent Contributor
timestamp: September 02, 2023, 11:58:51 am
content: Quote from: MarioBros69 on August 31, 2023, 09:24:29 pmYou doing it wrong!The manufacturer: making all conditions ideal.YOU: not doing it like the manufacturerA) You gotta load your PSU. Load with 1 amp through your multimeter.B) You gotta install two caps in parallelC) You gotta use probe without ground wire, directly with a paper clip or springD) You gotta turn off your lights and all other electronics in the room, including computerE) You gotta use 20 Mhz bandwidth limitF) You gotta use 1x probeG) You gotta use AC coupling...and even after all of this, you still would go out of spec, because you measuring at the output terminals of your PSU and not on your PSU's board.Basically, in repair, if it's out of wack it won't work, so if you see it out of wack too much and it don't work, assume it is out of wack.

author: sonpul
author_rank: Regular Contributor
timestamp: September 02, 2023, 12:32:11 pm
content: Delta, MeanWell...e.t.c. Use for the technical report such scheme.

author: BillyO
author_rank: Super Contributor
timestamp: September 02, 2023, 02:21:46 pm
content: Quote from: u666sa on September 02, 2023, 11:58:51 amIf you want to match the fairy tale the manufacturer is telling, that's the way to do it. If you want to see what is really going on use a 10X low capacitance probe and as much BW as you have available.I also really hate that they all require additional filtering to be added for the noise/ripple tests. The noise/ripple figures they provide should be as the power supply is. If they require that filtering, then they should include it in the power supply.Seems like it's all a smoke and mirrors fairytale throughout the PS industry. Why can't they just be honest?

author: MarioBros69
author_rank: Contributor
timestamp: September 02, 2023, 03:19:06 pm
content: Quote from: BillyO on September 02, 2023, 02:21:46 pmMy English is not too good..., but I understand that you advise me to use the probe at x10 and not activate 20Mhz?

author: BillyO
author_rank: Super Contributor
timestamp: September 02, 2023, 03:33:33 pm
content: Quote from: MarioBros69 on September 02, 2023, 03:19:06 pmIt is certainly up to you, but you need to decide what it is your after.If you want to match the manufacturers specifications you will need to use a 1x probe and use the 20MHz BW limit. Those along with other precautions like finding the and eliminating the source of ambient noise you are experiencing. Most PS manufacturers also apply additional filter capacitors too, like both a 10uF electrolytic and a .47uF ceramic across the output then attach the probe directly (no ground wire) as close as possible to the output.However, if you want to see the real noise and ripple you PS is generating use a 10X probe, full BW and do not put on the additional filter capacitors. You will still need to eliminate any ambient noise and attach the probe directly to the output.

author: BillyO
author_rank: Super Contributor
timestamp: September 02, 2023, 05:12:31 pm
content: For this test I'm using a small 5V 3A Mornsun SMPS.In both cases the supply was loaded to 2.5AThe first two pictures (next post) show the added capacitors and the 1X probe attached within 1cm of the PS terminalsThe green traces are with: Added 10uF and 1uF capacitors, 20MHz BW limit, and 1X probe. The first of these traces shows the ambient noise with this setup.The blue traces are with: No added capacitors, full 600MHz BW, and a Tek 10X P6205 750MHz 1.5pF probe. Again, the first of these traces shows the ambient.Note also the time base and vertical changes between the green traces and the blue traces.You can see that using all that filtering you really don't see the actual noise being produced by your PS. The ripple is essentially the same but there is a significant amount of HF noise that you would not otherwise see. You are figuratively sweeping the dirt under the carpet when using the ancient "industry standard" method.

author: BillyO
author_rank: Super Contributor
timestamp: September 02, 2023, 05:13:21 pm
content: Other pictures...

author: nctnico
author_rank: Super Contributor
timestamp: September 02, 2023, 05:22:43 pm
content: But how much of that noise comes into your scope through the ground and how much is actually between the +/- of the PSU?And measuring with a capacitor in parallel is not a bad idea because that is how most power supplies are used in the end.

author: BillyO
author_rank: Super Contributor
timestamp: September 02, 2023, 05:28:29 pm
content: Quote from: nctnico on September 02, 2023, 05:22:43 pmI have shown ambient traces (everything connected but PS off). I have also ensured that the ground from the probe to the PS is less than (much less than) 1cm. The noise being shown is being created by the PS.

author: nctnico
author_rank: Super Contributor
timestamp: September 02, 2023, 06:03:47 pm
content: Quote from: BillyO on September 02, 2023, 05:28:29 pmYes, but is the noise between +/- or ground induced? It is quite possible the PSU is pushing HF current through the ground connection of the probe which then shows up at the input. A differential measurement is much better.

author: BillyO
author_rank: Super Contributor
timestamp: September 02, 2023, 06:08:15 pm
content: Quote from: nctnico on September 02, 2023, 06:03:47 pmI don't have a differential probe and one that could catch those spikes would likely cost more than a new car so won't be happening anytime soon..What I can do is ground the negative on the DC side and see if that makes a difference.

author: nctnico
author_rank: Super Contributor
timestamp: September 02, 2023, 06:12:09 pm
content: Quote from: BillyO on September 02, 2023, 06:08:15 pmWhat you can try is reverse +/- and see which part of the noise flips up-side-down and what remains the same.

author: BillyO
author_rank: Super Contributor
timestamp: September 02, 2023, 06:22:56 pm
content: Quote from: nctnico on September 02, 2023, 06:12:09 pmWell, grounding one side makes things significantly worse (800mVp-p). I guess since the PS is already grounded that just created a big loop antenna.If I reverse things the ripple may indeed reverse, but the spikes are quite random and roughly symmetrical. They'll look the same anyway.Quote from: nctnico on September 02, 2023, 06:12:09 pmBTW, the PSU is being supplied with a ground. The only way to deal with this properly would be a differential set-up. Would two probes and the math "-" function work?

author: dophuc
author_rank: Contributor
timestamp: September 02, 2023, 06:56:32 pm
content: You can use an isolation transformer to power the PSU, which ensures the PSU is not grounded. And that's how I do it when testing PSU ripple/noise

author: tautech
author_rank: Super Contributor
timestamp: September 02, 2023, 07:04:36 pm
content: Quote from: dophuc on September 02, 2023, 06:56:32 pmAny decent PSU output should be isolated from mains Gnd.

author: BillyO
author_rank: Super Contributor
timestamp: September 02, 2023, 07:07:04 pm
content: Quote from: BillyO on September 02, 2023, 06:22:56 pmNope!

author: nctnico
author_rank: Super Contributor
timestamp: September 02, 2023, 07:07:21 pm
content: Quote from: tautech on September 02, 2023, 07:04:36 pmDefine isolated... You'll still have capacitance towards ground and neutral has a reference to ground as well. Together with the X and Y caps, you have all kinds of ground paths together with capacitive coupling to the surroundings.

author: tautech
author_rank: Super Contributor
timestamp: September 02, 2023, 07:19:55 pm
content: Quote from: nctnico on September 02, 2023, 07:07:21 pmMost of that should be on the primary side = isolated from outputs.

author: BillyO
author_rank: Super Contributor
timestamp: September 02, 2023, 07:29:08 pm
content: Even if some of this noise is common mode it's still noise being produced by the power supply and in many cases, like where the powered equipment if ground referenced or will be connected to ground referenced equipment, it becomes a factor. It will even affect circuitry it is attached to through currents created by radiated energy. I see no reason to ignore it by filtering it out.

author: nctnico
author_rank: Super Contributor
timestamp: September 02, 2023, 07:37:33 pm
content: Quote from: tautech on September 02, 2023, 07:19:55 pmIt isn't. Especially for switching power supplies / AC-DC converter modules. Due to parasitic capacitances in the transformer these will push HF current into the secondary side. The X and Y caps can short some of this current back to the primary side but without extra filtering (a common mode choke + some capacitors for example), this HF current will flow anywhere where there is a path of low resistance.

author: Fungus
author_rank: Super Contributor
timestamp: September 02, 2023, 07:41:16 pm
content: Quote from: MarioBros69 on August 31, 2023, 09:51:55 pmYou won't see any ripple unless the PSU is under load. More load=more ripple.

author: MarioBros69
author_rank: Contributor
timestamp: September 02, 2023, 09:15:31 pm
content: Quote from: BillyO on September 02, 2023, 07:29:08 pmThank you very much for all your posts, they have helped me a lot to understand how difficult it is to measure the ripple of a power supply.And it leads me to the next reflection, does it make sense to buy an expensive oscilloscope if you are in a noisy environment?

author: BillyO
author_rank: Super Contributor
timestamp: September 02, 2023, 09:24:37 pm
content: Quote from: MarioBros69 on September 02, 2023, 09:15:31 pmSure it does. Low level measurements are only one of the hundreds or thousands of use cases for a good oscilloscope.It would be worth while finding out what is casing your noise though. Then when you do need to make low level measurements you can disable/disconnect it.My normal environment is quite noisy to, in order to take the measurements I did today I had to turn quite a few things of around the house.

author: tautech
author_rank: Super Contributor
timestamp: September 02, 2023, 09:35:18 pm
content: Quote from: MarioBros69 on September 02, 2023, 09:15:31 pmNone at all. What you have now is fully capable for these tasks and better than most and offering 500uV/div sensitivity.

author: BillyO
author_rank: Super Contributor
timestamp: September 02, 2023, 09:37:47 pm
content: Quote from: tautech on September 02, 2023, 09:35:18 pmI don't think he's considering upgrading. I think he means his Sgilent is the "expensive" scope.

author: tautech
author_rank: Super Contributor
timestamp: September 02, 2023, 09:39:51 pm
content: Quote from: BillyO on September 02, 2023, 09:37:47 pm$379 expensive ?

author: BillyO
author_rank: Super Contributor
timestamp: September 02, 2023, 09:44:21 pm
content: Quote from: tautech on September 02, 2023, 09:39:51 pmIt's all relative. Compared to a Hantek or a Fnirsi it is or even to lower end Siglents and Rigols. It's 10 times the price of a DSO154 Pro!!

author: tautech
author_rank: Super Contributor
timestamp: September 02, 2023, 09:59:08 pm
content: Quote from: BillyO on September 02, 2023, 09:44:21 pmOffering the same sensitivity and BW....nope !

author: BillyO
author_rank: Super Contributor
timestamp: September 02, 2023, 10:03:59 pm
content: Quote from: tautech on September 02, 2023, 09:59:08 pmOf course not. Hey, you don't have to sell me on Siglent. You basically already did. To the tune of about $4K spent in the last 16 months.Just sayin' that there a lot of folks on the EEVBLOG forum to whom $379US is a lot of money.

author: tautech
author_rank: Super Contributor
timestamp: September 03, 2023, 01:27:20 am
content: Quote from: BillyO on September 02, 2023, 10:03:59 pmAnd some will learn hard lessons buying the cheapest, untested/unproven pretty looking gear.Also just saying.

author: BillyO
author_rank: Super Contributor
timestamp: September 03, 2023, 01:48:20 am
content: Quote from: tautech on September 03, 2023, 01:27:20 amI'm in complete agreement on this.However, in the extreme if all you have is $50 to buy a scope then a $50 scope is better than no scope. Think of it as a "gateway" instrument. The neophyte will learn some things and be able to visualize signals which will aid their progress in their electronics hobby to the extent they will eventually find themselves in need of a better instrument and understand the value in the purchase price.

author: tautech
author_rank: Super Contributor
timestamp: September 03, 2023, 02:16:57 am
content: Quote from: BillyO on September 03, 2023, 01:48:20 amInstead many also learn a scope is just the start, HV, differential and current probes are also must haves andinvestmentsin that can be used on any scope although it is very useful to have input attenuations settings that can match any probe instead of in your head calculations like we had to do with CRO's.Back in them days I played a lot with magnetics and then you could find the great P6021 current probe for under $100 but sadly far less so these days.CRO's, I had a few and several Tek DSO's also, none of which can compare with modern DSO's of the last 5 or so years.

author: BillyO
author_rank: Super Contributor
timestamp: September 03, 2023, 02:46:21 am
content: Quote from: tautech on September 03, 2023, 02:16:57 amI'm looking to expand (it's a disease, I tell ya what!) but I think a real differential probe will never be a part of my kit. But maybe a half decent current probe.I just bought a new truck. A Toyota Tacoma with all the trimmings. I usually take good care of my vehicles and it will probably last me 15-20 years. It cost $56K. It's kind of funny but that kind of money is a pittance to what you can spend buying a TOTL oscilloscope or other piece of best in world test equipment. But those are on a different level. For the most part they can't even be applied to the stuff most of us work with. You literally have to design the DUT to be tested by them.Anyway. I still have 2 CRO's. Kind of a part of my hobby is to use vintage test equipment to work on vintage electronics. I even have a separate "vintage" bench.One scope is a venerable Tek 465, the other I just picked up recently for $40, is a Heathkit IO4205.It's a 2 channel, 5MHz monster from the 80's and is a total nostalgia boost for me. My first scope ever was the Heathkit IO4105 I built in 1980. The single channel version. Speaking of boot times .. 7 seconds to visible traces. Anyway, it may be ancient and it may be a CRO and it may be as big as a microwave oven, but it's a darn sight better instrument than any cheap little $40 2" screen, single cahnnel 200KHz scope like the DSO138.

author: tautech
author_rank: Super Contributor
timestamp: September 03, 2023, 04:48:17 am
content: Quote from: BillyO on September 03, 2023, 02:46:21 amMostly a differential probe doesn't need to be too flash but provide good voltage isolation.Something like the old DP25 used with care can serve you well.https://www.pintek.com.tw/productDetail/land-ctop-2/index/pscsn/17072/psn/19265QuoteNever ever spent that much on wheels.QuoteYet as you know for what your new wheels cost you can now set up a very respectable lab with what the leading Asian brands offer.QuoteBasically that's how I got/fell into this game after fixing my first gifted CRO when in my 40's as life had been too busy to continue with electronics since a childhood start.After fixing many more and a few DSO's I knew they were the future in the reliability stakes.QuoteNot sorry to say I gave the CRO bit up completely some 10yrs back when I got a 300 MHz DSO and regrets are none.However I do count myself lucky to have been along for the ride with Siglent and 9yrs is too long since I last visited them. However not sure I want nasal passages explored just to get clearance to get on a flight to Shenzhen.

author: BillyO
author_rank: Super Contributor
timestamp: September 03, 2023, 05:18:14 am
content: Quote from: tautech on September 03, 2023, 04:48:17 amIt's a bit marginal on the BW, but beyond that they seem to have a lot of interesting products. However, I don't think they are interested in retail sales.I guess if I can find another 9999 interested parties we could get a container of them at a reasonable price (maybe a bit of an exaggeration, but maybe not).But thanks Rob, I appreciate the discourse.

author: tautech
author_rank: Super Contributor
timestamp: September 03, 2023, 07:36:07 am
content: Quote from: BillyO on September 03, 2023, 05:18:14 amIt will suit most needs.QuoteYes Pintek have minimum buying limits which works fine for us.They do have a few resellers and have been around for years however mainland Pintech have stolen their designs and customers.

author: Performa01
author_rank: Super Contributor
timestamp: September 03, 2023, 08:37:23 am
content: Quote from: MarioBros69 on September 02, 2023, 09:15:31 pmThe SDS1202X-E is low noise with true 500 µV/div sensitivity. It can't get much better than this, regardless of the price.No matter how expensive a scope is, it won't help you with the environment. About the only way to get rid of environmental (= common mode) noise is to use differential probes. Even though the active probe support found on the more expensive midrange scopes might encourage the use of such probes, this is not much more than a matter of convenience.

author: Fungus
author_rank: Super Contributor
timestamp: September 03, 2023, 11:18:21 am
content: Quote from: MarioBros69 on September 02, 2023, 09:15:31 pmYou can usually work on the background noise to reduce it.

author: Fungus
author_rank: Super Contributor
timestamp: September 03, 2023, 11:20:11 am
content: Quote from: tautech on September 02, 2023, 09:39:51 pmYep, and this is your blind spot...

author: Fungus
author_rank: Super Contributor
timestamp: September 03, 2023, 11:22:01 am
content: Quote from: tautech on September 02, 2023, 09:59:08 pmBut not everybody needs that. 500uV and 200MHz will make no difference at all to the average Arduino hacker.

author: Caliaxy
author_rank: Frequent Contributor
timestamp: September 03, 2023, 12:35:58 pm
content: Quote from: dophuc on September 01, 2023, 05:48:30 pmNo 50 ohm termination?

author: tautech
author_rank: Super Contributor
timestamp: September 03, 2023, 01:42:30 pm
content: Quote from: Fungus on September 03, 2023, 11:20:11 amYou think ?My eyes are wide open and can well see the poo that's offered to the marketplace.....bit of a shame buyers of that poo don't have their eyes open too.

author: MarioBros69
author_rank: Contributor
timestamp: September 03, 2023, 03:24:06 pm
content: What I wanted to say is, what's the point of buying a 500 uV/div oscilloscope if I have such a noisy environment?Anyway, after reading and learning from your answers, I understand that the first thing to do (if that is possible) is to avoid the source of noise.My intention is to buy a 1104X-E but they sent me a 1202X-E by mistake, I have returned it and in the next few weeks I have to decide which one to buy, so read this forum a lotBy the way, the more I read the forum the more money I want to spendAt my age (55 years old) and my little knowledge of electronics belongs to the era of analog oscilloscopes, I recently decided to return to electronics as a hobby and I am buying some equipmentThis week someone close to where I live sells me a KIKUSUI 5060 analogue in good condition for just under 100 euros and since my knowledge of electronics is limited maybe it is enough for a simple hobbyI have many doubts" alt="" class="bbc_img" />

author: nctnico
author_rank: Super Contributor
timestamp: September 03, 2023, 03:32:57 pm
content: Skip the old crap unless you want to have a hobby keeping your equipment running.

author: markus_jlrb
author_rank: Regular Contributor
timestamp: September 03, 2023, 04:53:57 pm
content: If you could not effort or use diff probes, I would like to recommend abattery drive scope like the OWON HDS2xxx devices.40MHz BW -> HDS2042(S)70MHz BW -> HDS2072(S)100MHz BW -> HDS2102(S)200MHz BW -> HDS2202(S)The S-models include a build in 20MHz sig. generator (sinus) 5MHz (rectangle) and arbitrary sig. formats.For a beginner it is more secure as you avoid the GND/shortage problematic while taking your measurements.Nevertheless it's important to understand how to connect DSO/Scope and DUT in a secure way to avoid a damageof your device and/or your DUT.Markus

author: MarioBros69
author_rank: Contributor
timestamp: September 03, 2023, 05:57:18 pm
content: Quote from: markus_jlrb on September 03, 2023, 04:53:57 pmThank you very much for the advice, after reading many in this forum my current idea is to buy a 1104X-E but I will also take your advice into accountDo you mean that since the oscilloscope is portable and not connected to 220v, I will no longer have noise when taking the measurement?

author: Performa01
author_rank: Super Contributor
timestamp: September 03, 2023, 06:27:55 pm
content: Quote from: MarioBros69 on September 03, 2023, 05:57:18 pmA battery operated scope can measure differential signals (i.e. wihout ground reference) with some griefs when in a pinch, but that does not magically turn the single ended (asymmetric) scope inputs into well blanced differential ones. Consequently, the common mode rejection will be quite bad, especially at higher frequencies.Sensitive measurements require proper probing techniques, simple as that. Yet a modern DSO can help you with this, even when the signal of interest is drowned in environmental noise. For instance, just to measure the ripple of a linear power supply, you could use AC line triggering and average acquisition mode to get the signal clearly visible and make precise measurements.

author: Martin72
author_rank: Super Contributor
timestamp: September 03, 2023, 07:25:12 pm
content: Here is a short paper concerning ripple measurements, mainly on switching power supplies.

author: MarioBros69
author_rank: Contributor
timestamp: September 03, 2023, 08:05:06 pm
content: Quote from: Martin72 on September 03, 2023, 07:25:12 pmThank you for the document..., it is very interesting

author: tautech
author_rank: Super Contributor
timestamp: September 04, 2023, 07:07:37 am
content: Quote from: MarioBros69 on September 03, 2023, 05:57:18 pmLet's look a little harder atthisparticular measurement.It's a linear PSU with isolated channelshoweverthere is provision to tie any output to mains Gnd:(middle terminal)When doing so the antenna effect of a probe reference lead is much reduced as this places the reference lead at the same mains ground potential and noise should be substantially reduced.Screenshots please when you get your SDS1104X-E.

author: MarioBros69
author_rank: Contributor
timestamp: September 04, 2023, 01:06:52 pm
content: Quote from: tautech on September 04, 2023, 07:07:37 amDo you mean that I should connect the negative of the oscilloscope probe to the ground terminal and the positive of the probe to the positive terminal?I have doubts about the purchase, now someone tells me that instead of the 1104X-E I should spend a little more and buy the Rigol MSO5074The more I read the more doubtsThanks

author: tautech
author_rank: Super Contributor
timestamp: September 04, 2023, 08:47:43 pm
content: Quote from: MarioBros69 on September 04, 2023, 01:06:52 pmThat's what happens if you ground (link center terminal) the negative side of the PSU output.Passive probes don't have negatives and positives, the reference lead is always at mains ground potential in all scopes except isolated channel versions.QuoteIf you want to see even more noise at low signal levels the 5074 has substantially more system noise that excludes it from precise low level measurements.QuoteGood, members knowledge can help you understand and grow.

author: Martin72
author_rank: Super Contributor
timestamp: September 04, 2023, 09:03:18 pm
content: QuoteIt's difficult, but doable.I found it too annoying at the time, so I switched to the SDS2104X+.