How to measure a single event on scope. - Page 1
Forum section: electronics / beginners

author: chinoy
author_rank: Regular Contributor
timestamp: April 22, 2022, 06:27:41 am
content: I have read all the manualls.Watched hundreds of videos and tried every which way from sunday to get this reading.I know its possible cause 10 years ago I did use a scope and did get a reading. That scope I no longer have.The objective to get get a wave from. From different types of coils. i.e. experiment with gauge thickness and number of turns.Next is to observe how a resistive load across the coil impacts the signal. And 3rd is to see how the polarity of the wires impacts the signal.This is a single event. i.e. A magnet will be passed over the coil.And we need to capture the signal.So far all I see is a lot of noise.I suspect the problem is to do with the fact that the lowest average is 4. i.e. the scope wants 4 signals before it displays it.Right now I can only give it one. I set the trigger fro single 1 volt positive slope. I pass the magnet over the coil. It gets triggered but all I see is a flat line.In my old fluke there used to be an option which said catch transients. Cant find that on my new hantek. I purchased this scope just for this work and was up the whole night trying to grab s clean signal.A bit down in the dumps.Its a 100 Mhz Scope with 100 Mhz probes.Today I will dig out my old Fluke and try with that. Will post pic of the coil in a bit. Its a 40 Ohms small coil.

author: jonpaul
author_rank: Super Contributor
timestamp: April 22, 2022, 06:48:30 am
content: Works fine,on Tektronix scopesUse single trigger mode, setup, push reset adjust trigger levelMost analog scopes have similar single shots.My Yokogawa digital scopes have same.Perhaps the Chinese forgot to copy this,most,basic scope trigger function?Jon

author: Terry Bites
author_rank: Super Contributor
timestamp: April 22, 2022, 01:46:43 pm
content: Hantek make 100's of products- who knows? What kind of noise? It sounds like you havent set up the trigger for the signal of interest. Check your scope manual for "single shot" or "SINGLE SEQ".

author: chinoy
author_rank: Regular Contributor
timestamp: April 22, 2022, 01:50:00 pm
content: No the hantek has the function. What its missing is the auto voltage and time delay setting that my 20 year old Fluke had.How I solved this was to use the fluke. Auto time base and auto trigger option. This gave me my voltage range and my time base range i.e. 1 Volt and 20 Ms. These values we auto detected as the best values for a single shot. Based off a single sample I gave it.The hantek can do the same. But it expects a steady stream of repeated pulses.I copied these values over to my Hantek and it started to show me a wave form on single capture.I had been playing with the trigger voltage values on the hantek.The fluke auto sets everything for you i.e. the voltage and the time base. For the single shot capture.My Fluke body is disintegrating on me.I really need to find a clean shell and keyboard foil for it. When nothing else works it always saves my ass.This is the coil.https://drive.google.com/file/d/1g4gLWmAtA0Hu-tRsHoeTL9RJ_PHKAqjn/view?usp=sharingWhat Im trying to figure out what impact the shape of the V cut out has on the wave form. Some coils come with a flat metal plate and some come with this V-Cutout.The other thing Im trying to figure out is what is the impact of taping your signal positive off the top or the side. On this coil one wire is signal and the other is ground.

author: chinoy
author_rank: Regular Contributor
timestamp: April 23, 2022, 12:29:27 pm
content: The shape of the cut out impacts the wave form shape just in case anybody wanted the answer.Now my next problem replicating that wave form via a function generator. lol

author: StillTrying
author_rank: Super Contributor
timestamp: April 23, 2022, 01:28:52 pm
content: Why are you giving all kinds of details of the coil but none of the scope.I'll be surprised if it can't do Type Real Time, Mode Normal, and Trigger Normal.Lower the memory to reduce the waiting time before and after the single capture.

author: chinoy
author_rank: Regular Contributor
timestamp: April 24, 2022, 05:50:56 am
content: Its a hantek DSO1052P series scope.I did play with that screen. In some modes I cant change the number of samples. And in others I can at best lower it to 4 samples.The problem is this is single shot capture i.e. when the magnet passes over the coil. I want the wave form captured. Im only going to get one shot. The signal does not repeat.Guess it boils down to getting the right time base. When you have no reference its painful to try every time base till you get something that works.But thanks for pointing me to the right screen I guess I need to spend more time understand the options offered on that screen.Your right about the memory need to figure out how to change that.Im having a friend drop by and give me a few lessons. He says Im a typical fluke guy. Because I like stuff that is idiot proof.This is where fluke shines. But if you learn how to use a bench scope anything can be done on it.

author: StillTrying
author_rank: Super Contributor
timestamp: April 24, 2022, 02:48:32 pm
content: "hantek DSO1052P"?"In some modes I cant change the number of samples."With Acquire set to Real Time & Normal the Waverform Averaging will Off, so you don't have to worry about whatever the number of averages is.I usually start with the trigger level 1/2 to 1 division above the 0V trace, and then with the trigger on Normal or Single just dabbing a finger on the unconnected probe end to check it's capturing.For the relatively slow edges from a coil you'll want the Channel DC Coupled to get an accurate shape.

author: chinoy
author_rank: Regular Contributor
timestamp: April 28, 2022, 11:15:05 am
content: Thanks for all the help and tips.If any of you guys are in my neck of the woods Id love to take you guys out for a beer.Had a friend come in and give me a quick class on using bench scopes.We got the best signal on the coil by using a/cI had to rig up a small gig. A thin sheet of plastic which kept the gap between coil and magnet constant.We also learned what happened when you switch the polarity of the probes on the coil.In one way. The wave form starts with an upward sine wave. And in the other position. The curve starts downwards and then moves up.As the circuit only triggers on the up slope. Swapping the wires results in a slight delay. This was the answer we were looking for.