Show a beginner why and how to use oscilloscope. - Page 1
Forum section: electronics / general

author: Teljemo
author_rank: Contributor
timestamp: October 19, 2014, 08:29:18 am
content: Everybody is using oscilloscopes.I cant afford one right now but i have a friend who placed hes in my electric corner..But i want to use it.. i don't know how and why..read that its great to find faulty circuits and such..cant find any good guides for first time beginners..i would love to see an episode that makes me understand why and how i NEED the oscilloscope and that makes me dependent of it in the future

author: EEVblog
author_rank: Unknown
timestamp: October 19, 2014, 08:34:41 am
content: I've had a few request for this now, so I think I might do something along these lines.

author: tggzzz
author_rank: Super Contributor
timestamp: October 19, 2014, 08:57:09 am
content: Quote from: Teljemo on October 19, 2014, 08:29:18 amThe starting point is to understand that a scope shows how a voltage varies over time.If, and only if, you can interpret the significance of the voltage correctly, you can find out what is happening inside a circuit. If you understand how a circuitoughtto be behaving then you can compare it with how itisbehaving - and possibly understand what is/isn't working.

author: Teljemo
author_rank: Contributor
timestamp: October 19, 2014, 05:33:13 pm
content: Sound great.. Looking forward for it

author: Hydrawerk
author_rank: Super Contributor
timestamp: October 19, 2014, 06:38:11 pm
content: https://en.wikipedia.org/wiki/Oscilloscopeor maybehttps://sv.wikipedia.org/wiki/Oscilloskop

author: Teljemo
author_rank: Contributor
timestamp: October 19, 2014, 07:12:35 pm
content: Good reading.But no one can explain it like Dave on the vlog

author: Philbywhizz
author_rank: Contributor
timestamp: October 20, 2014, 04:34:01 am
content: Hello,My First post (been lurking a bit), and this thread got my attention.I have recently got the 'bug' in getting back to electronics again (after about 20 years of hiatus) and I have even obtained a little 10Mhz 1 channel analog scope to help with my re-learning.I consider myself a beginner (self taught).I would love a video on how to use a scope for simple stuff and what kind of things you can do with it.Perhaps a few simple example circuits to hook up to show different things (I built a quick astable 555 circuit and they went to see if I could see the square-wave output, and I did!! (it was awesome to see and achieve that). I then threw in some caps on the output to see if I could smooth the pulses out. Changing out different components an seeing and measuring the effect on the scope (and not just looking at a blinking led) was quite educational! But I'm hungry for more!Cheers,Phil.

author: Teljemo
author_rank: Contributor
timestamp: October 20, 2014, 06:52:51 am
content: I haven't got that far yet.. compared to mePhilbywhizzyour an engeneer

author: tggzzz
author_rank: Super Contributor
timestamp: October 20, 2014, 08:31:26 am
content: Quote from: Teljemo on October 20, 2014, 06:52:51 amPhilbywhizz has the right idea: try something, make mistakes, make new mistakes.The secret of successIs simple to expressTo errand errand err againBut lessand lessand less(Piet Hein)The major mistakes you should avoid are touching a high voltage, putting too high a voltage across the scope input (e.g. switching off current flowing thorough a motor or inductor), and earthing the wrong point (or worse, disconnecting the earth).Dave has a video w.r.t. earthing the wrong point; seehttp://www.eevblog.com/2012/05/18/eevblog-279-how-not-to-blow-up-your-oscilloscope/

author: Philbywhizz
author_rank: Contributor
timestamp: October 20, 2014, 11:36:53 am
content: Quote from: Teljemo on October 20, 2014, 06:52:51 amThanks for that, but if I'm an engineer then this board is full of Einsteins!Quote from: tggzzz on October 20, 2014, 08:31:26 amYes, that is a great video. After watching it I was feeling more confident on using my scope, and safely so I wouldn't 'blow it up'. Maybe in the future I'll upgrade to a Rigol once the confidence builds, but for now this one allows me to learn and play.I don't intend on playing around with any mains or high voltage systems - I'll leave that to the real engineers. I'm only interested in low voltage (microcontrollers and digital circuits), and most of those would be battery powered (or via a 'floating' (is that the correct word?) power supply).Because of this I'd be keen on how to use an analog scope for working with digital circuits (and is it possible?).

author: ServiceXp
author_rank: Contributor
timestamp: October 20, 2014, 09:54:37 pm
content: Quote from: tggzzz on October 20, 2014, 08:31:26 amUnfortunately I don't think he mentions transformer less power supplies.

author: tggzzz
author_rank: Super Contributor
timestamp: October 20, 2014, 11:07:56 pm
content: Quote from: ServiceXp on October 20, 2014, 09:54:37 pmThere are also many other things he doesn't mention in that video.

author: ServiceXp
author_rank: Contributor
timestamp: October 20, 2014, 11:14:33 pm
content: Quote from: tggzzz on October 20, 2014, 11:07:56 pmI figured as much; can you share some?I only mention it (as it pertains mostly with power supplies) as I recently made that mistake

author: tggzzz
author_rank: Super Contributor
timestamp: October 21, 2014, 08:43:07 am
content: Quote from: ServiceXp on October 20, 2014, 11:14:33 pmIt would be dangerous for me to make a few off-the-cuff remarks where personal safety is concerned. I might express myself poorly, not mention something that is obvious to me (but not to you), etc, - and you might hurt yourself.A good starting point is the websites of reputable oscilloscope manufacturers. They have many pdf documents about why their equipment is the way it is, and how to use it. Tektronix is particularly good , as is HP/Agilent/Keysight.Have a look atYou definitely can use a scope to look at digital signals, but you will need to be aware of the relationship between time and frequency, and of probing techniques.The information below is probably more advanced than you need at this stage. It is a cut-and-paste of something that I have told other people in similar circumstances.A key point is that for digital circuits a good strategy is to:first use a scope to ensure the really-analogue-but-interpreted-as-digital signals are clean (i.e. good power and signal integrity), being careful of the way the scope and probe interact with the circuitthen debug digital problems in the digital domain, using logic analysers, or single stepping through your code, or using printf logging statementFor RF circuits, you probably want to avoid using scopes:for RF signals: spectrum analysers have a much more appropriate noise linearity and dynamic range specificationsfor RF components: vector & network analysers have similar advantagesbut scopes are more useful when looking at the demodulated signals or simple power envelope.Remember the key equation for scopes and probes:trisetime= 0.35 / bandwidth (e.g. 3.5ns <=> 100MHz, and the fundamental frequency/period is irrelevant)In an ideal world you would have the scope's risetime sufficiently short that it can capture the fifth harmonic of the signal's risetime, e.g a 500MHz scope+probe for a 3.5ns signal risetime; in practice you can usually infer what's happening using a lower bandwidth scope.Rules of thumb for signals and suitable probes, but remember that rules can be broken:audio frequency analogue <-> croc(k)-clip or *1 probe<50MHz analogue or low-speed digital <-> *10 probeRF <-> 50ohm coax or very expensive active probesdigital <-> 500ohm low-impedance Z0 probe, or very expensive active probes, (or *10 probe)special purpose <-> differential probes, high voltage probes, current probesN.B. you can't make your own *1 or *10 probe, but you can easily make your own 500ohm low impedance Z0 probe; see below.Scope safety:floating measurements, differential probes:http://info.tek.com/www-fundamentals-of-floating-measurements-and-isolated-input-oscilloscopes_ty.htmlblowing up scope via ground:And for probe fanatics:Quick probe overview:http://www.williamson-labs.com/scope-probes.htmGood intro to probes:http://circuitslab.case.edu/manuals/Probe_Fundamentals-_Tektronix.pdfQuirky but informative about probes:http://www.dfad.com.au/links/THE%20SECRET%20WORLD%20OF%20PROBES%20OCt09.pdfComprehensive probe theory, long and old:http://www.slack.com/TE/TekConcepts/TekProbeCircuits.pdfTwo videos:http://www.ganssle.com/video/episode1.htmlhttp://www.ganssle.com/video/episode2_whats_in_a_scope_probe.htmlDIY homebrew 500 ohm low impedance "Z0" probehttp://emcesd.com/1ghzprob.htmandhttp://elektrotanya.com/files/forum/2009/10/e04a036.pdf

author: miguelvp
author_rank: Super Contributor
timestamp: October 22, 2014, 03:37:17 am
content: Let's not forget w2aew excellent tutorial on the beginners forum:https://www.eevblog.com/forum/beginners/oscilloscope-training-class-(long)/