WTB: oscilloscope - Page 1
Forum section: electronics / general

author: tizi
author_rank: Contributor
timestamp: April 17, 2017, 08:41:41 am
content: Hi All,as this is my first post please be GENTLE, lol.i have never used an oscilloscope but have to start some time, i have seen daves video on youtube stating try analogue get you feet wet .willing to start with analog oscilloscope or delve straight in to digital. my location is adelaide sa.budget for analoque ??If i went for digital my budget would be $500Q.) what to look for brand, mhz, etc..any help would be appreciated tizi

author: tautech
author_rank: Super Contributor
timestamp: April 17, 2017, 09:08:55 am
content: Welcome to the forum.Without some electronics experience the risk of getting a CRO and it breaking down should not be overlooked. Without experience and some other equipment you may not be able to fix it and therefore might loose the cost of it.Because of this the rule of thumb for price is usually only ~$1/MHz bandwidth.There is much help here and online to understand oscilloscope use so if you can afford it go for a modern DSO.

author: tggzzz
author_rank: Super Contributor
timestamp: April 17, 2017, 09:43:25 am
content: You don't know what you want - or, more usefully, need. That's a good starting point. Thus the "touchstone" question at the moment is "how do you find out what you need?".There are several ways to answer that question, one of which is to ask questions on a forum.Another is to get something, anything, and try to use it to solve your current problem. Doing that will enable you to understand what your tool can andcannotdo; once you know that you will be in a better position to specify (not guess) what youneed.All tools have a learning curve. If you are a beginner, then it is advantageous to have a simpler tool so that the learning curve is shorter - and you can get results more quickly. Complex tools can be daunting to a beginner; a particular problem is that sometimes necessary controls/settings are not visible because they are hidden in a menu system.Taking those points into consideration, consider getting a cheapworkingold scope; the £1/MHz isn't a bad rule of thumb. That implies paying maybe £30 for a 20MHz scope, or £50 for a 40MHz scope. Use that scope and, when youknow whyyou need another, get therightone for you. Either save the remainder of the $500 for the next scope or, more likely, for other equipment you find you need - e.g. a bench PSU or sig gen etc.Consider the Digilent Analog Discovery, especially if you can get the educational discount. That is relatively simple, and remarkably capable since it includes signal generators and post-processing software for things like spectrum analysis, and a logic generator and analyser.The major advantage of a digitising scope is that it can capture transient one-off events. You will find that, with thought imagination and skill, most (but not all) cases where you need a scope can be turned into repetitive events, thus reducing the perceived advantage of digitising scopes.You might like to skim (don't read the whole thing!)https://www.eevblog.com/forum/testgear/siglent-they-filed-a-'wrongful-trademark-claim'/and look at people's .sig.

author: tautech
author_rank: Super Contributor
timestamp: April 17, 2017, 09:49:08 am
content: @ tggzzzWhat relevance does the link you have offered have with this thread ?

author: tggzzz
author_rank: Super Contributor
timestamp: April 17, 2017, 10:07:17 am
content: Quote from: tautech on April 17, 2017, 09:49:08 amThat's for the OP to decide.

author: tautech
author_rank: Super Contributor
timestamp: April 17, 2017, 10:12:44 am
content: Quote from: tggzzz on April 17, 2017, 10:07:17 amOK so you want to play silly buggers.

author: nctnico
author_rank: Super Contributor
timestamp: April 17, 2017, 03:08:58 pm
content: AFAIK Dave already recalled that video where he suggests to start with an analogue scope because analogue scopes are seriously outdated nowadays and digital oscilloscopes have many features which make taking measurements easier. Perhaps it is better to read several of the many 'I'm looking for an oscilloscope' threads in the test equipment section. From there you should be able to make a list with what is important for you and how much money is sensible to spend.

author: james_s
author_rank: Super Contributor
timestamp: April 17, 2017, 07:01:04 pm
content: I still always suggest people start with an analog scope and learn the fundamentals and then get a DSO later and be amazed at how much easier certain things are, also armed with the knowledge of why it works the way it does, having used the analog scope previously. Since perfectly good analog scopes can be found for around $50 or less it's a very small investment and depending what you're doing it may turn out to be all you really need. We used analog scopes for decades and accomplished all sorts of things long before DSOs were affordable.Similarly if you wanted to learn to fly a B737, you'd probably start out flying manually in something like a Cessna to learn the fundamentals of flying an airplane by hand before working your way up to a big jetliner with fancy automated systems.

author: tggzzz
author_rank: Super Contributor
timestamp: April 17, 2017, 07:31:32 pm
content: Quote from: james_s on April 17, 2017, 07:01:04 pmPrecisely. But I would start with gliders, so you can have some fun rather than being in a car in the sky

author: rustybronco
author_rank: Contributor
timestamp: April 20, 2017, 06:04:14 pm
content: I'll put my two cents in.I bought a used TDS360 to replace my old Tektronix 2235AN/USM488 analogue scope. I much prefer it over the controls used in the 2235. If it were me starting to use an oscilloscope, I would purchase a TDS340A, 360 or 380. They can be had, at least here in the States, rather cheaply and they don't have the same issues with leaking caps like the 4XX and 5XX series of the same model line. I'm sure other brands have their respective models that are user friendly, reliably built and have the service manuals necessary to repair it in case something does go wrong with it.One area that needs to be noted, the Dallas RTC's are getting long on tooth with these models so having a spare (getting had to find) and (or) removing it and having it cloned with the existing information on it may not be a bad idea.

author: james_s
author_rank: Super Contributor
timestamp: April 20, 2017, 06:16:59 pm
content: The Dallas chip is definitely something to watch out for in the TDS300 series scopes. I've somehow ended up with a small stack of TDS300 and TDS400 scopes, the 400's are significantly more feature-rich instruments but the power supplies seem to be unreliable, they're a very strange design and a real bear to work on. Both of my TDS340 scopes have lost their calibration constants which are stored in the DS1644. It's easy enough to hack out the old battery and replace it with a new one but calibration requires some specialized equipment. I have the DC voltage calibrator and have managed to get that part done but I'm still working on something to calibrate the timing. The calibration routines in these are very fussy and will fail if the signal is not within a very narrow window of what it expects.Nice instruments when working, a bit old but still plenty capable, but I would not pay more than $100 for one that was not in fully working order with a new DS1644 or new battery and some sort of calibration. If you have to pay someone to calibrate it that's another $200 or so on top of the cost of the scope although they can be used uncalibrated if you don't mind seeing the calibration fail error each time you power it up. I got the ones I have because I'm enjoying the challenge of restoring them but for somebody completely inexperienced who wanted a DSO to use rather than a project I'd probably suggest they just buy a Rigol or other low end new one.I'm still going to recommend that someone completely new who just wants to get their feet wet should find the cheapest working analog CRO they can find, don't pay more than $50, aim for maybe half that, just get something that works and learn how to use it, and that includes understanding how to interpret the graticule with the time and volts per division. Then you will have a reasonable idea of what you want in a scope if you choose to stay with the hobby, and you will really appreciate newer features like readouts and cursors.

author: Joel_l
author_rank: Frequent Contributor
timestamp: April 20, 2017, 06:28:39 pm
content: I would think of analog vs low end DSO ( price range ) more like learning to fly in a 70s 172 vs a 2000s 172 with glass cockpit. They will feel the same but one has tools that can make life easier once you get the basics down.Quote from: james_s on April 17, 2017, 07:01:04 pm

author: james_s
author_rank: Super Contributor
timestamp: April 20, 2017, 06:35:44 pm
content: I'd chose the 70s plane with steam gauges every time personally, but maybe I'm just old. A panel full of dials and switches just looks the way an airplane should IMO. I'm a manual transmission guy too, wouldn't have it any other way.

author: tautech
author_rank: Super Contributor
timestamp: April 20, 2017, 08:43:14 pm
content: Quote from: james_s on April 20, 2017, 06:35:44 pmThis is a point that we often overlook. I'm well into my 50's but in the last decade or so we have had to move into all manner of menu driven appliances instead of those with just knobs, switches and gauges.The young generation know little else and have little trouble adapting to the next/latest device dropped in their laps. Core to adapting is an understanding of what a gadget/scope does and how to drive it to get the measurements you need but I do agree to the uninitiated a modern DSO can be daunting but I argue less so for the younger. Again, it's understanding and not turning on ALL the bells and whistles which only clutters the display and can obscure the important basic information. I rarely use OSD measurements which I guess dates from my CRO use days when we got all the info directly from waveform/graticule relationships without even thinking.DSO newbies can't often do this instead they turn on "Measure All" or the like so there is no thought of how to find the values from the graticules and they then can concentrate on adjusting the scope to get correct waveform information. This can lead to a state of information overload and lead to mistakes being made BUT it's so very easy to prevent...turn off Measurements, use captures and study what you havestaringyou in the face.The best bit of advice I got with my first scope was to havesomeidea of the waveform expectedbeforeconnecting a scope.This presumes one has an understanding of circuit operation which should be a prerequisite before connecting probes but is sadly less so these days.That begs the next question for the novice/newbie; how to get some understanding of circuit operation ?Theoryorownership of a tool that lets you see what's going on ?Now we're back to square one......how to use a scope and which is best to learn with for a novice/newbie, CRO or DSO ?

author: james_s
author_rank: Super Contributor
timestamp: April 20, 2017, 10:29:18 pm
content: Heck I'm not even 40, but a friend of mine once commented that I was the youngest old guy he knows.Now get off my lawn! Damn kids.

author: tizi
author_rank: Contributor
timestamp: April 21, 2017, 12:53:15 am
content: hi all,found an ad in our local paper for a oscilloscope Tektronix 2211 no probes for $260 seems a bit pricey to me, but then again what do i know.q.) how does one test with out knowing what to do other that powering on

author: xrunner
author_rank: Super Contributor
timestamp: April 21, 2017, 12:59:53 am
content: Quote from: tizi on April 21, 2017, 12:53:15 amIf it doesn't have probes (and neither do you ) you could take a piece of small wire and connect the center pin of each channel to the calibrator output. You should see a square wave of some lowish freq. In DC mode you can make it deflect up or down in with a 9V battery. What I'm telling you is pretty lame testing, but if you can't do anything else and want to take a risk, if you see positive results, you can take a chance.

author: james_s
author_rank: Super Contributor
timestamp: April 21, 2017, 02:51:51 am
content: Quote from: tizi on April 21, 2017, 12:53:15 amThat sounds really high to me. I know the used test gear market in Australia is not what it is in the US, but that's an old and rather primitive DSO. I had a quick peek on ebay and there are loads of 2211 scopes for under $150.Personally I would say look for an old scope that is maybe $50 or less, or just buy a new Rigol or other low end DSO and call it good. Don't pay top dollar for an older scope unless you have a specific reason for wanting that particular unit.