DSO138 Oscilloscope Kit Performance Evaluation
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- Опубликовано: 16 дек 2017
- Taking a look at the JYE Tech DSO138 kit oscilloscope against a Rigol DS1102CD to see how well it can measure and represent a sine and square wave across the bandwidth.
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There is a simple improvement you can make that solves a problem where the waveform might look a bit raggedy with high input signals. It seems that the voltage divider resistances R6, R7, and R8 are low enough to put a bit too much load on the output of amplifier U2B. Since the divider feeds into the non-inverting input of U2C, you can just raise those resistance values by 10 times with no issues. And you get a cleaner waveform. Use 1% resistors. This also applies to the smaller DSO138 "Mini" version.
This was extremely helpful sir. I am looking at building some guitar pedals and wanted to get an idea of how the waveforms would change with different components, and this cheap and cheerful piece of kit could be a perfect answer to my prayers. Much appreciated.
Glad to be of help. I might be working on some guitar circuits myself at some point. I just received a stomp box on off switch from eBay as my starting point.
I bought it for soldering practice. That fact that it can actually be used for say, something simple under the hood of a car... Just to get a very rough idea, well that's just a bonus. Thanks for your time!
Have you used the DSO138 for automotive work, and what specifically did you test? I just ordered a Wave2 0-200KHz for an attempt to confirm if my car's alternator (generator) has an AC ripple voltage. I"m second guessing the bandwidth and thinking maybe it might make sense to go with something in the range of 5MHz, so I don't end up with a useless trinket. I've searched far and wide for examples of different real-world applications/examples of where one would find various Hz in electronic devices. The closest I found was this spectrum table with power lines 50-60 Hz and computers with 60-100 Hz: www.cancer.gov/about-cancer/causes-prevention/risk/radiation/electromagnetic-fields-fact-sheet I see plenty of youtube videos with people adjusting Hz with signal generators, but no real-world examples where they could actually be observed. I would appreciate any helpful hints. Does anyone have links of Hz tables or spectrum charts with which device sine wave square waves would be present? Does saving a waveform provide an opportunity to attempt determine a waveform that's outside of the devices bandwidth?
The bandwidth rule of thumb is to use a scope with 5 times the bandwidth of what you need. If you want to measure 20 MHz signals you need a scope with 100 MHz. A 200 KHz scope would be good to 40 KHz which is very close to your results. It would be interesting to see how the real scope worked when fed signals at the same percentage bandwidth as the DSO138.
I have one of these. It helped me diagnose a problem with an inverter which was supposed to be pure sine wave. I discovered it was actually a modified sine wave inverter that was mislabeled!
I just bought one to make wiggly lines because I’ve no idea what it does !
Same.. It's beautiful and you look very smart in front of your girlfriend.
The best 20$ spent, no doubt!
LMAO 🤣🤣🤣
Lol
Is it still working😅?
After a couple of months of building kits and playing with a 555 I bought a DSO 138 to play with. I knew it was just a toy but I figured it would help me decide if a scope was something I thought I needed.
I'm glad I got one cause it helped me learn a bit about using a scope and a few areas where I thought a scope would be helpful.
My Rigol 1054z is so much more useful obviously, but it makes me wonder how much longer it would have taken me to see the need for a scope without that 138.
I see you everywhere on these electronics channels comment section.
This is *exactly* why I got a DSO138 (and indeed the 1054z is where I think I may go next... *if* I find the DSO138 useful). Glad to know it wasn't such a daft idea from someone who already walked that path.
All oscilloscopes attenuate as you go up in frequency. That's why the general rule of thumb is to buy one with a bandwidth 5 times higher than the highest frequency you will be using it on. That would put this one at 40 kHz for use which was pretty close to your results. I ordered the newer updated mini version in a kit with case for $11.87 shipped free but haven't received it yet.
From 20Hz to 20 KHz, it will do it will work. Thank you for your work!
That's what I need lol
Thanks for the ☺️ neat and clean review.
Thanks for making this video. It was very helpful
Thanx. You saved me some coins. I was hoping all waveforms would work at 50khz. Thanx for the great useful review.
I bought it on aliexpress for 7 € and for simple measurements it is good...
Thanks for the review!
My DSO138 is also good to about 30khz.
Pretty good for a $12 oscilloscope, you get what you pay for.
My old Tectronics 2246 cost a few more.
Nice video, thanks.
This this is good for audio only. But a good teaching tool.
Nice vid.
change out the ceramics for less temperature dependant ones and this machine improves another 50k
Good idea - would you recommend searching digikey or the like? Hey maybe make a "upgrade / mods" video
@@drz4073 That would be a great idea
Great demonstration. Have you tried changing the V div to see if the voltage reading is more accurate? And have you tried changing the calibration trimpots?
It’s been a while since I did the testing and I can’t remember how the accuracy looked at different voltage division scales but I remember setting the calibration to get a good one kilohertz square wave that would trigger properly and look to be the right amplitude and sharp edges, it needed a little tweaking. I had some sort of offset problem but it went away. I should take it out and try it again now and see if the calibration has drifted as well.
Hello, very nice video ! i an new to oscilloscopes and i would like to ask you some questions about DSO138:
1- What is the difference between the BNC and P6100 probe
2- For DC current should i hook to both negative and positive of the component to see it waveform ?
3- For AC current only positive of the probe or both ?
4- What is the purpose of the alligator probe linked to the P6100 ?
5- Can i see the waveform of 220v of the mains ? with which probe ?
6- What is the 1x and 10x of the P6100 probe ?
7- I want to see the waveform of some PWM of PSU ATX rated at 500Khz, is it possible ?
Thank you very much !
thank you a lot
Muito bom! Posso usar em som automotivo para limpeza de sinal de 20hz - 20khz?
Thank you.
I'll be honest I haven’t a clue how to use one, like someone else said I bought mine for the welding practice. At the moment I'm just at the beginning of learning about the Arduino UNO and I have heck of a lot of basics to learn yet. Mine was only £15 though and it comes with an acrylic/Perspex case. I'm just looking forward to the project, though I just have a cheap soldering iron so we'll see how that goes. I think I might need to upgrade my soldering station before my oscilloscope.
Thanks
I am very beginner in electronics , and can not afford a big osciiloscope , will this be fine for learning basics?
plz let me know so i can tell my parents to get this for my birthday! :)
as long as you use it within its specifications for voltage and frequency limits, it’s good for basics like putting it on the output of some oscillator circuit and seeing the waveforms and checking their frequency and voltages
thank you
I hope the information was helpful.
Thaks for rewiew
Can be use it to mesure automotive sensors and signals? .And for example to measure the pure sine inverter?
I wouldn’t use it if accuracy is required but just to get a general idea if something is operating or not, as long as the input voltage isn’t exceeded, I would just use it to see if there’s any signal at all rather than trying to accurately measure the signal.
Hi , I curious how to show the info over DSO 138 ?
So couldn't you modify some of the values of the components to increase or decrease its available measurement range and time adjustment? Thinking of picking one of these up to look at guitar pedal signals. Thanks!
Not sure if much can be done in just hardware part swapping to change bandwidth/timing because it would be all software and processor silicon capability related too.
I guess larger input amplitudes could be just scaled down with a resistor voltage divider, like adding an attenuation probe, and smaller signals can be amplified with an op amp or something to get them into detectable range if they are too weak, if it's just to get a visual of the signal and not needing the readout to be accurate and not concerned about any new introduced noise or error offsets.
Should be able to see the output of a pedal with the range of this scope, the pedal output being somewhere less than a volt up to theoretical max of whatever the pedal runs as, maybe 9V.
How did you get all that info on the top part of the DS0138 ? I have the same model but it seems like I can't get in any mode that will display the duty cycle, peak to peak voltage, etc. Are you powering the DS0138 from your computer via a USB cable ? I can't see any connectors on the top part of the oscilloscope.
Yeah nvm I just held the "OK" button for 2 seconds and the readout activated.
Can this detect/display 5 - 10 Hz?
It can go up to 500 second per division. So 1hz is a piece of cake.
Can anyone use it for viewing/measuring noise level and ripple voltage of an smps output?
Maybe if the frequency is within a few tens of KHz it may be visible but switching regulators might be in the hundreds KHz and this device may not recognize it. I would never use such a low-cost unit for anything serious, it’s more a visual novelty.
@@GadgetReboot Thank you very much for the opinion. Best regards.
Can we connect the probe to +12 and -12 supply. that is 24Vpp?
The manual says it can take 50v peak, 100v p-p and I see that the op amps have a split +/- supply suggesting it can take +/- inputs (as a scope should) so it sounds like it can do +/- 12
www.elecrow.com/download/UserManual_138_new.pdf
@@GadgetReboot Thanks for the reply and for the manual. I have ordered this scope. I will check it with +/- 12v input supply. Hope it will not damage with 24Vpp input.
Hello. Very Nice vídeo. Can you teste a situation of Hight Frequency Transient with one of your less espensive oscilloscope? Like a mini-motor conect to the eletricity home net.
I'm a geobiologiste and the so call "durty eletricity" it's an important matter of safety at home. I'm from Portugal and I'm already a fun. Thank you very much!!!
Would this work For adjustment of output to amplifiers for car audio to fine tune the system?
should be able to easily
@@jacksonzheng3103 thank you for your answer
HII AND THANK YOU
Can IT be use to automotive, to diagnoze cars. ? for example sensors or CAN
Depends what is needed, it may be able to show slow changing signals but it only has a bandwidth of 200 KHz, while CAN bus can be way faster signals
@@GadgetReboot THANK YOU
ALOT.
My DSO138 always scrolls to the left.Do ya think it's broken? Or is it me?
sounds strange, some sort of weird roll mode? I wonder if there are firmware updates we can do.
@@GadgetReboot Ya. I never did flash a new firmware on it. Perhaps that is it. Thanks.
but this is the main point it does not say for professional use it states for hobby and educational use it is a basic piece for beginers thats what you get when you oay not much so i would say it is a pass mark for me, great video cheers
The DSO138 scope tested
➡ Read this article
chinese-electronics-products-tested.blogspot.com/p/dso138-very-cheap-scope-tested.html
Ok, but much faster to just turn the frequency up until you hit an attenuation of 3dB, thats the bandwith.
Yeah, if it was a normal piece of equipment it would be a lot easier to check the endpoints of its operating limits but this one was a bit quirky.
One of the main reasons I slowly went through the range was to show where non-sine waves start to get visually distorted as well as where the voltages start to become less reliable on the display.
Overall I didn’t want to go through all of its features but just wanted to show that it should be OK for audio bandwidth..
And try to adjust trigger level and base time. It will stabilize the wave and you will get more stable values.
its good to use at 20khz
IS THERE ANY HACKER DOWN THERE???
The real questions is: "What are the limiting factor?"
How can we improve the quality of theses ultracheap O's?
-Getting a better probe?
-Install metal shielding around some components?
-Replacing the capacitor (or any cheap component) with something else?
-Get a 9V battery instead of a cheap 9V wall transfo (like I do to save on battery cost)?
I'm not an electronic guru, I only have some basic knowledge and RUclips as a perpetual teacher.
Alex from Montréal
As you can see from the video, the 200 kHz claim is unrealistic. One issue is the bandwidth of the analog input circuitry resulting in the loss of amplitude. But the main one is how well the wavevorm can be handled given the digital sample rate. it is pretty common for such scopes to still read the frequency to something pretty high because that is really a different function in the scope. Bandwidth tends to be decidedly exaggerated on all of the "mini" scopes (and perhaps somewhat exaggerated on many others). Furthermore, not to get too technical, but the algorithm used to divine a waveform from very few samples thinks in terms of a sine wave unless it has enough sample points to think otherwise. While 200 kHz is claimed, more like 100 kHz is the limit for a sine, and 30 kHz (at best) for a square wave. But since many of these are used for people doing audio work, it can do the job surprisingly well for spending about 25 bucks and then either buying a battery or a maybe a $5 wall supply. How this comes shipped has changed a bit over the years and the instructions may not exactly match. And this is especially true for jumpers. On both the DSO138 and smaller DSO138 "Mini", it may already have jumpers installed (as zero ohm surface mount "resistors") where the instructions say to bridge the jumper with solder. So you don't have to. Or there may be a jumper it says is already factory bridged, but isn't.
The number of 200 is not exactly unrealistic per se
The rule of thumb with scopes is that you are good upto 1/5 of the bandwidth, which would be around 40kHz here and clearly it works well upto that point so it does what it is supposed to do.
@@MaxC_1 I guess that rule of thumb depends on what brand scope you buy. I have used many Tektronix scopes where the specifications were accurate. 100 MHz meant 100 Mhz and that's what you got. Even an old Hitachi V212 hobby level analog scope nearly met its specifications vastly better than 1/5 of the claimed bandwidth. What the mini-scope manufacturer claims it is "supposed to do" is, however, is 200 kHz, not 40 kHz. Another "rule of thumb" is the Nyquist theorem (sampling frequency being 2X is sufficient) which some exaggerated specs depend on and since this is a 1 MSa/s scope that would suggest the even more ridiculous 500 kHz bandwidth. Having used, and calibrated, test equipment for over a half century, your rule of thumb may apply to the low cost cheap stuff out there, but certainly not to reputable brands.
Does it matter that you measured AC in DC mode?
DC mode just allows any offset voltage to also be measured instead of centring the AC around ground.
@@GadgetReboot Got it, thanks!
200MHz advertised bandwidth?
Oops. Don’t know how I made that typo and never noticed it for a year. I’ve updated the description to kilohertz. Thanks. Maybe I should re-watch it and see if I said it verbally as well.
@@GadgetReboot
I use mine just as a novelty visual display for the output of my sound system, so the kHz spec is fine for my purposes. My hearing is long past hearing even any semblance of 20kHz anyway- :)
My original idea for buying it was also a novelty for the monitoring sound effect generating and other audio things which I hope to do more of this year. If I could afford it I would like to get into some modular synthesizer stuff.
The last time I watched one of those RUclips hearing tests that sweep up in frequency with an annoying tone, I could get somewhere over 14 kHz out of my ears. At least now I have a baseline if I check in another couple of years.
So for audio acquisition it's good?
Yes it appears to work well for audio frequency range, which is well below its marketed bandwidth. I wouldn't use it for anything too far above audio but that's all I wanted it for so it worked out.
BAMOKINA MOANDA Destin so are you using this device to tune your stereo equipment your amplifier so you won't have clipping
Yeah I used it to get a clean sine wave out that didn’t distort so I would know when I am operating in the right region for one small project I had. I might do a video on something like that.
if you up a better opamp will do better.
Thanks
Thanks