12 Replies Latest reply on Mar 3, 2020 5:45 AM by msbettyhunt

    Oscilloscope tutorials

    cyberwasp

      Can anyone point me to a good tutorial on oscilloscopes. I've been watching a lot on YouTube but they seem to skip practical applications and make adjustments without stating why. Also they tend to end even though they state there will be follow up videos.

       

      My main goal is to get comfortable with the scope and I would like to duplicate a video I saw on YoutTube that was using a scope to watch the charging current on a tp4056 li-ion charger.  TIA

        • Re: Oscilloscope tutorials
          shabaz

          Hi Steven,

           

          I've not watched these completely, but these two seem ok for the essential controls:

          How to use an Oscilloscope part 2 of 5

          Measure Period, Frequency and Amplitude on an Oscilloscope part 3 of 5

          They are slow-going though. I don't like it when they waste too much time on humour, because I'd rather spend that time watching a comedy if I wanted that : ). There's a PDF lab series here, which is more technical and to-the-point, and prompts you to try out things... it relies on a more modern 'scope with built-in signal generator, but you could use other signal sources (e.g. a phone with jack plug and WAV files could work at a pinch):

          http://www.ee.ic.ac.uk/pcheung/teaching/DE1_EE/Lectures/Lecture%203%20-%20Electrical%20Signals%20&%20Oscilloscope%20(x2)…

          That document refers off to this video:

          MAKE presents: The Oscilloscope

          I think 'Art of Electronics' had a good chapter on oscilloscopes too - I can check my copy if you plan to purchase any books on a recommendation.

           

          Also, bear in mind that modern 'scopes are multi-purpose tools, so you may get the impression that 'scopes do very little unless you check the datasheets and user manuals of modern scopes. Then you'll see that you may also need tutorials on things like signal generators, logic analyzers, and maybe even spectrum analyzers. They may not all apply to your current goal of course. Most people first get familiar with observing simple waveforms without much noise, and repetitive, like sine or square waves, to learn the basics - amplitude+coupling, timebase and trigger.

          Plus, to really understand the subtleties of using scopes there's more intensive stuff to learn about probes, transmission lines and sampling, which may be glossed over in a general oscilloscope tutorial, simply because the subject is too big. Incidentally, 'scopes generally measure voltage, not current, so you'd need to make a decision how you intend to interface your circuit to a probe to measure the quantity of interest. There are specialist probes but they cost a lot. I'm wondering if you're using a traditional x10 voltage measuring probe, which is what one normally sees in beginner oscilloscope tutorials.

          11 of 11 people found this helpful
          • Re: Oscilloscope tutorials
            fmilburn

            Hi Steven,

             

            You don't mention the model of your oscilloscope but some of the larger manufacturers have very good training material for their specific 'scopes.  For example, Keysight provides excellent training for the DSOX1102GDSOX1102G which I wrote about here Entry Level Oscilloscope Comparison:  Keysight, Rigol, Siglent  and even used to assess other oscilloscopes.  The Keysight training does require the built-in wave generator on the DSOX1102  to get full value however.  Other manufacturers such as Rigol provide good training for their 'scopes as well, e.g.:  https://www.rigolna.com/basics-of-oscilloscopes/ .  This can be applied to other models if the manual for your oscilloscope is consulted alongside.  In any event, try looking for training from the manufacturer for specific capability if you haven't already done so.

            7 of 7 people found this helpful
              • Re: Oscilloscope tutorials
                beacon_dave

                "...The Keysight training does require the built-in wave generator on the DSOX1102  to get full value however..."

                 

                The non built-in wave generator versions (i.e. missing the G suffix) of the 1000 X series scopes still have the training waveforms built-in, so it only really prevents you from doing 1 of the labs:

                 

                   Lab #6 Using the WaveGen Built-In Function Generator

                 

                in the Educator's Training Kit for 1000 X series lab manual.

                 

                The EDUX models don't have segmented memory acquisition so you can only do:

                 

                   Lab #14 Using Segmented Memory to Capture More Waveforms

                 

                on the DSOX1000 models.

                 

                However even the basic EDUX1002AEDUX1002A model is sufficient to complete 12 out of the 14 lab exercises.

                3 of 3 people found this helpful
                • Re: Oscilloscope tutorials
                  cyberwasp

                  Sorry, my scope is a Siglent SDS1102CML+ 100Mhz model . I know there's better but didn't go that route as I only use it as a hobby to keep me busy. In the good ole' days I was always throwing together radios, counters,  from parts my dad brought home from work along with other numerous things. I haven't built anything since other than computers Which I now at 63 use for my job..

                   

                  I have the basic understanding and am well versed using a multimeter. I've calibrated the probe and set it at 10k. I recently watched a video from a guy  using an Arduino to show basic measurement with the scope 

                   

                  What intrigued me though was a video using a tp4056 to charge a Li-ion battery which I do weekly as I've become my neighborhoods "solar light repairer."  In the video he had his scope measuring the batteries charge And current draw. However he was using the older TP4056 and I haven't yet to identify the same point on the new version with battery thermal and overcharge protection.

                   

                  From the tp4056 data sheet it should be the PROG(Pin 2): Constant Charge Current Setting and Charge Current Monitor Pin which I've yet to find.

                   

                  "Can't take it with you unless you keep practicing!!!"My tp4056. Need to fix the neg input joint

                  4 of 4 people found this helpful
                    • Re: Oscilloscope tutorials
                      fmilburn

                      I had the SDS1102 CML as well and that is one of the oscilloscopes included in the comparison link I gave above.  In that comparison I give a brief description of capability and how to use various functions of the 3 scopes so it may be worth a look for you.  I used the Siglent for a number of years and found it intuitive to use but the manufacturers training for that model was lacking comparatively. That may no longer be the case for their newer scopes, I haven’t looked.

                      Your battery charger project sounds interesting and I imagine you can get help on that here on element14 with a new post.  Give it a title like how do I measure current on a LiPo battery charger or something like that and outline what you have done along with links to datasheets if you have them and other relevant information.  I am not clear why a scope is needed but a sketch with how they were hooking up the scope would be helpful.  Once that is known applying the Siglent to the problem is probably straight forward.

                      3 of 3 people found this helpful
                      • Re: Oscilloscope tutorials
                        shabaz

                        The explanation in the TP4056 PDF datasheet was a little hard to follow, but it does appear you could measure the voltage at pin 2 to determine if it is in pre-charge or not. However, it would be easier to determine that using a multimeter set to amps, in series with the power source. If the current is high then the battery is not in precharge state.

                        To determine if the battery is charged or is in a charging state, then pins 6 and 7 can be examined, according to the text below, extracted from the datasheet. None of this needs a 'scope (although if you have it it is a good opportunity to use it), a multimeter could be used (and if desired LEDs attached to pins 6 and 7 as shown in the circuit further below). If you mean to use the scope to plot a chart over time of the battery terminal voltage, or current, or something else, then normally an oscilloscope is not used, because it is such a slow-changing thing (the charging may take at least an hour normally. Some multimeters will log data, or some code could be written to capture this from a 'scope, or something like 'Analog Discovery' could be used. It would be an unusual thing to measure though, because for a repair all you'll usually care about is if indeed the battery is charging or not, if it does reach the termination state, and how long the charged battery operates the product. I may have misunderstood your requirement.

                         

                        6 of 6 people found this helpful
                          • Re: Oscilloscope tutorials
                            cyberwasp

                            Shabaz. My reason for using a scope to watch the current is mostly just a learning experience with the scope. Even back when I was hip deep in transistors and such I couldn't learn by seeing but when I actually built a circuit and physically started measure values off of components and traces did it make sense. Back than it was an analog voltmeter the size of a toaster.

                             

                            What's been bugging me is when the guy in the video did it, why can't I. Hope that makes sense.

                             

                            Here's the video I'm trying to duplicate. https://www.youtube.com/watch?v=wfrm6lbt8Pc&t=630s

                             

                            TIA

                            1 of 1 people found this helpful
                              • Re: Oscilloscope tutorials
                                shabaz

                                Hi Steven,

                                 

                                What happens when you try to monitor the same connections? What are the settings you're using? A screenshot or photo will indicate this.

                                In the video it is hard to tell but I think he's got the horizontal scale (i.e. timebase) set to 100 seconds per division, which is extremely long. He's not directly monitoring current, he is monitoring pin 2 (see the datasheet snippet in my previous comment) which supplies a voltage proportional to the current apparently.

                                That's his yellow trace I believe. The red trace is connected to the battery I think (I didn't watch the entire video), so that he can see the battery terminal voltage simultaneously too.

                                 

                                This is an unusual use-case to learn with, because you don't need to make use of the things worth learning when using a 'scope, i.e. triggering, the 'scope may act differently too, e.g. go into a not-frequently-used mode (rolling mode) and it's hard to understand scale and position with a slow signal. It's easier to practice on a more normal repetitive signal (like a sine wave or square wave) at a frequency where you can quickly see the response and determine what happens with the scale, position, input coupling and so on.

                                He's using the 'scope as a chart recorder if anything.. Anyway, there's no reason why your 'scope won't display the same thing too, provided the triggering is disabled or set to auto mode, or if you hit the single trigger button (I don't have the same 'scope but it should be visible somewhere on your 'scope too), and provided your timebase is set to such a slow speed, and so on. It's not a special thing that his 'scope is doing, other 'scopes will do that too.

                                You're not going to find many youtube videos showing such settings, since this isn't frequently done. The thing worth reading up on is oscilloscope triggering modes, that's possibly where you're getting stuck, although I'm guessing, because I cannot see your 'scope settings.

                                3 of 3 people found this helpful
                                • Re: Oscilloscope tutorials
                                  fmilburn

                                  Expanding a bit on what Shabaz says... The Siglent User Manual states the scope can be set down to 50 s/div which while not as slow as the video is very slow.  I never used mine for something like this but would advise you to push "Auto" first to make sure the scope is triggering after connecting the probes.  You should see the traces for both channels.  Then using the Horizontal position control move the start left to where it is just within the screen.  Next turn the Horizontal as slow as it will go, i.e. 50 s/div.  You should be able to do a single shot (upper right hand) if desired after getting the controls set as well.

                                  3 of 3 people found this helpful
                                    • Re: Oscilloscope tutorials
                                      fmilburn

                                      I Was thinking about this as I took my morning walk.  As Shabaz said, this is an unusual case and for most of the time it is seeing a very slowly changing DC voltage instead of a repeating wave form it can trigger on.  When Auto is pressed as I suggest above it will probably think you are interested in the noise on the DC input and set the vertical scale down in millivolts when you want volts.  So it will be probably be necessary to adjust the vertical scale up as well.  

                                      1 of 1 people found this helpful