function generator/oscilloscope synergies - Page 1
Forum section: electronics / beginners

author: dalpets
author_rank: Contributor
timestamp: February 11, 2024, 12:53:06 pm
content: What basic synergies need to be satisfied for a meaningful & practical pairing of a function generator & oscilloscope for diagnostic purposes?Can an oscilloscope be programmed to do anything meaningful without a function generator or other hardware?

author: dobsonr741
author_rank: Frequent Contributor
timestamp: February 11, 2024, 02:52:56 pm
content: The test scenario drives the tool selection, not the other way around.

author: MarkT
author_rank: Frequent Contributor
timestamp: February 11, 2024, 11:55:37 pm
content: Quote from: dalpets on February 11, 2024, 12:53:06 pmA synergy cannot be satisfied, that makes no sense grammatically. I think you need to be more concrete in your question and give examples.

author: dalpets
author_rank: Contributor
timestamp: February 12, 2024, 10:29:17 am
content: Quote from: dobsonr741 on February 11, 2024, 02:52:56 pmCan you give me an example?

author: tggzzz
author_rank: Super Contributor
timestamp: February 12, 2024, 10:53:50 am
content: Quote from: dalpets on February 12, 2024, 10:29:17 amThat would be a neat comment, if there was a smiley afterwardsYouneed to supply the "use-case" examples, and only thereafter is it sensible to derive the tool selection.The alternative is to find a way to use whatever is available. That's a valuable skill, but irrelevant to your question.

author: dalpets
author_rank: Contributor
timestamp: February 12, 2024, 10:54:43 am
content: Quote from: MarkT on February 11, 2024, 11:55:37 pmMy question is perhaps grammatically naive but makes sense to me. It's not the sort of technalize jargon you would probably expect to be used, but please take the time to realize that you are dealing with a complete beginner.Putting language semantics aside the best way I can rephrase the question in simple English is HOW does one decide what parameters to call up in the function generator that will satisfy specific & subsequent oscilloscope diagnostics, Surely they are not selected in a willy nilly manner!I can't give examples because I lack the experience to do so. My question is more in the vein of procedural theory.

author: tggzzz
author_rank: Super Contributor
timestamp: February 12, 2024, 11:04:33 am
content: Quote from: dalpets on February 12, 2024, 10:54:43 amThat is completely different to your first post!Quote from: dalpets on February 11, 2024, 12:53:06 pmasks how you can best use a function generator and scope to diagnose a problem - presumably in a UUT, since that is normal usage of the two.Your "redefined" question is about how to use a function generator to test a scope.First you define what parameter you want to measure, the parameter's expected values, the required precision, and - most importantly -whyyou want to measure it.After that, you can work out the equipment settings necessary.

author: dalpets
author_rank: Contributor
timestamp: February 12, 2024, 11:31:43 am
content: Quote from: tggzzz on February 12, 2024, 10:53:50 amTouche! So how does a green horn get started then. There must be a multitude or infinite number of "use case examples" in which case it would seem to necessitate a university degree and/or substantial experience in the electronic industry to have the necessary mentoring & acquire the necessary skills. So where does that leave the ardent hobbyist! To use a religious comparison- there is no room in the inn. Forget it! That is, unless you can work backwards with a good dose of examples. Does that even exist in the hobby wild west?My hardware is a Siglent function generator (SDG1020) & Siglent digital oscilloscope (SDS1102CML). I also have a Keysight oscilloscope (EDUX1052G) on the way that utilizes training kits, so I am serious about learning but I may have bitten off more than I can chew given the sparse resources available at my beginner level..

author: dalpets
author_rank: Contributor
timestamp: February 12, 2024, 11:39:38 am
content: Quote from: tggzzz on February 12, 2024, 11:04:33 amTo clarify intentions. My aim is not to test a scope but to use the scope to diagnose separate circuit boards.

author: tggzzz
author_rank: Super Contributor
timestamp: February 12, 2024, 11:53:27 am
content: (N.B. two responses crossed in the æther!)Quote from: dalpets on February 12, 2024, 11:31:43 amAsk the right question. Giving the right answer is easy. Asking the rightquestionis more difficult – but is more interesting and rewarding. The answer to the right question will either cause you to go this way or that way, or will illuminate aspects that you didn’t even realise you needed to know.Tell us your problem/goal, as well your solution. In most walks of life, technical or non-technical, if we know the reason for the question you will probably get a better answer. Either the answer will be more pertinent to your needs, or perhaps it can suggest a better alternative that you haven’t even considered. Don’t ask “Can you give me a lift into town?” Do ask “Can you give me a lift into town, so I can replace my broken frobnitz?”. The answer might be “There’s a spare frobnitz in the attic”, thus saving time, money, the environment – as well as making some space in the attic.QuoteNo, you (probably!) haven't bitten off more than you can chewI'm not familiar with precisely those pieces of equipment, but the generic principles will apply.Set up the function generator to give a waveform.Attach the scope and fiddle with the controls until you see a waveform [old CRT scope: use the beamfinder. modern digitising scope: cheat with the autosetup button]Use eyeball to measure various parameters, to check they match what you are expecting. Use scope's automated measurement facilities for the same purpose.Where there are differences between expected values and measured values: read equipment's specs, think, ask specific question.Possible points of contention: amplitude (sig gen voltage assumes correct termination (50ohms), square wave risetime and overshoot.Change waveform, rinse and repeat.When you start to look at real UUTs:don't try to measure any mains-related values (e.g. SMPS inputs) without appropriatetypesof probe, lest there be a loud noise and smokedo understand how scope probes change measurements, both by affecting the UUT and because of their inherent characteristicsnever disconnect the scope's earth, since that is connected directly to the scope's case and the probes' shieldsFFI, have a look at the references athttps://entertaininghacks.wordpress.com/library-2/scope-probe-reference-material/Finally: have fun, safely.

author: Andy Chee
author_rank: Super Contributor
timestamp: February 12, 2024, 11:55:52 am
content: Quote from: dalpets on February 12, 2024, 11:39:38 amThe function of the circuit board will dictate the appropriate diagnostic equipment and procedure.For example, diagnosing a faulty switch mode power supply circuit board, is different to diagnosing an Arduino circuit board, is different to diagnosing a radio transceiver circuit board, is different to diagnosing a motor control board, is different to diagnosing a faulty flat panel TV.This is often why laboratory equipment shelf is full of different pieces of equipment used for different tasks. In the test equipment world, there is not really such thing as a multi-tool swiss army knife.

author: Vovk_Z
author_rank: Super Contributor
timestamp: February 12, 2024, 02:31:32 pm
content: Quote from: dalpets on February 12, 2024, 10:54:43 amBoth functional generator and an oscilloscope are very universal general use devices. You may google your question and find a lot of answers with videos on Youtube. I don't understand why you are asking it (or what are you are talking about?). You question has a lot or too much answers.

author: MarkT
author_rank: Frequent Contributor
timestamp: February 12, 2024, 08:49:11 pm
content: Quote from: dalpets on February 11, 2024, 12:53:06 pmLets be clear, if you need a signal generator, you need a signal generator.If you need a scope, you need a scope.Having both won't make them any better, the 'scope will still be a 'scope, the generator will still be the same generator, there is no direct "synergy", but having only one will limit what you can do (they do different things) Think Venn diagram.If there's a synergy its between the test equipment and the user - the test equipment makes the user more capable, the user gives the test equipment purpose...

author: Shock
author_rank: Super Contributor
timestamp: February 12, 2024, 11:59:53 pm
content: Quote from: dalpets on February 11, 2024, 12:53:06 pmModern digital bench oscilloscopes and function gens come with a good range of features out of the box. It depends on the circuit/component you are building/repairing/diagnosing/analyzing and to what function or resolution you need as to if the pairing is suitable or practical. Starting out though, you can use any gear you get your hands on.The oscilloscope needs a waveform/signal/voltage source to look at, there's typically a probe compensation point on the front of the oscilloscope you can use to take your first measurements. It's good practice to go through the oscilloscopes manual and learn all the features while playing. Hook up the function gen and you can make and manipulate different waveforms/signals.There are specialist tools for generating or analyzing more specific signals but be hesitant purchasing more expensive gear until you understand exactly what it does.

author: dalpets
author_rank: Contributor
timestamp: February 13, 2024, 11:15:52 am
content: For beginners, replies here indicate that generalizing about the use of test equipment is non productive.So, moving on from there, and having watched numerous videos online I find it very interesting how the probing of circuits produces different wave forms that to the experienced eye can provide diagnostic information.While I would not be in a position at this stage to draw any conclusions from such probings I feel I need to start somewhere with my digital scope and generator & I think that starting point for me might be to see how in practice circuits respond to those probings.There are probably many circuit boards that would lend themselves to such testing but can you suggest any that would stand out from an educational point of view?Probably battery powered boards would seem to be a good starting point although in time I could move on to using an high voltage isolating probe and/or an isolated power supply for safety with circuits, both of which I already have.

author: Andy Chee
author_rank: Super Contributor
timestamp: February 13, 2024, 11:37:18 am
content: Quote from: dalpets on February 13, 2024, 11:15:52 amThe simplest circuit would be an astable 555 circuit on a breadboard. You can probe different pins, change component values, etc. And observe all the effects on the oscilliscope. You might be able to use your function generator to FM modulate the 555.An Arduino might make the next best candidate, you can program the PWM to work as an arbitrary waveform generator, albeit low resolution & frequency, but good enough to experiment with your code and see the results on the scope.If you want to test your function generator as well, the simplest circuits are lowpass, bandpass, highpass, and notch filters.

author: robca
author_rank: Frequent Contributor
timestamp: February 14, 2024, 08:12:06 pm
content: One of the classic use cases, is for an audio amplifier. Inject a signal of the right frequency, say 1kHz, check how the signal looks in different parts of the circuit. Change wave and frequency, see how well the amplifier works at different frequencies. Square waves are challenging (because a 1kHz square wave needs a much higher bandwidth to be properly amplified with no distortion).If the amplifier has tone controls, see how those change the signal.If you have 2 identical amplifiers one working, one not, you can use a signal generator and an oscilloscope to find the fault. If you understand how an amplifier works, you can find faults just with a signal generator and an oscilloscope.Strictly speaking, a signal generator is not needed. You could use a 555 to generate a signal to troubleshoot audio circuits, and most digital circuits don't require a signal generator to troubleshoot. I have been messing around with electronic projects for the best part of 45 years, and didn't own a signal generator until a couple of years ago (and it's gathering dust now). I'm not saying it's a useless device, because it's not, but of all the tools for a hobbyist, I'd put an oscilloscope, logic analyzer, multimeter, programmable power supply, good soldering iron and even a stereo microscope well above a signal generator as a general tool.Also, depending on your field, you might need completely different signal generators. For logic work, a pulse generator and a logic analyzer are much more useful. For audio circuits, all you need is a simple 100kHz signal generator that you can easily assemble out of spare parts. For RF work, you need a completely different beast, much more expensive.

author: hamster_nz
author_rank: Super Contributor
timestamp: February 14, 2024, 10:47:29 pm
content: An oscilloscope lets you visualize what is going on at one or more points in a circuit.A function generator lets you apply a known stimulus to a circuit so you can see how it reacts.You will have different requirements for each, depending on what you are doing.You could get started using something like an "Analog Discovery II" which can make your laptop act as function generator and an oscilloscope. For breadboarding circuits they are ideal.Or for an entry level stand-alone unit like a "Hantek DSO2D10" which is a low end scope with a signal gnerator, and can be had for about US$250. It would be idea for faultfinding and diagnostic work of already constructed circuits.I have them both and have used them and found them adequate for their price and specification. It's like with multimeters. You could spend US$250 on premium multimeter, but for low power hobbyist chores a $20 ANG AN8008 is a perfectly valid and very usable tool.