Beginner Oscilloscope Best Approach to Purchase Now or Later?

[rstofer]

Rstofer's comment about the signal reflections was a good reminder that my skills are not quite there yet, I'd have no idea about that if I was troubleshooting today.

They show up as ringing in a scope trace.  Hopefully, the probe doesn't load the signal so much that the reflection only occurs when not probing.  Ringing wasn't my first thought with that project either.  The thing about FPGAs is that they are FAST.

What's interesting in terms of equipment though is that it seems like if you never know what project you're going to work on then you'd almost have to buy progressively more powerful equipment.  Pictures of engineer's labs are often filled with tons of equipment, is it gear acquisition syndrome where they are buying new toys to use even though they could get by with what they have, or is it built up because they repeatedly have to buy faster/better/stronger gear that will match the increasing difficulty of their projects?

Clearly, you don't buy a multi-GHz scope to fool around with Arduinos.  When you get to the point where you are working at frequencies beyond your test equipment capabilities, you buy something else.  Or work at lower frequencies.  Keysight makes a scope that costs $330,000 plus accessories.  I'm not in the market...

Really, that's why we're talking about entry level scopes.  The more inexpensive scopes that are adequate for a good long time.  We're all aware of the limitations of entry level scopes and don't feel that we need something more capable or we would mortgage the house and buy something else.

[james_s]

Yeah, too ambitious for a first project, I was just trying to think ahead at what equipment capabilities I'd need when the time came to tackle it a year or two from now.  Rstofer's comment about the signal reflections was a good reminder that my skills are not quite there yet, I'd have no idea about that if I was troubleshooting today.  What's interesting in terms of equipment though is that it seems like if you never know what project you're going to work on then you'd almost have to buy progressively more powerful equipment.  Pictures of engineer's labs are often filled with tons of equipment, is it gear acquisition syndrome where they are buying new toys to use even though they could get by with what they have, or is it built up because they repeatedly have to buy faster/better/stronger gear that will match the increasing difficulty of their projects?

A lot of people just like collecting gear, look at anybody who is an enthusiast and has been into something for a while and they will probably have accumulated quite a large collection of related items. More serious professional engineers will typically buy a new piece of gear when they need it for a specific project, or they too might just see something that looks like a fun toy and decide to upgrade if their budget allows.

You can never have too much bandwidth, or too many channels, just like you can never have too much bench space, too much storage, too big of a workshop, too much land, too big of a boat, too much memory in your PC, too much money in the bank, etc. No matter how much you have there are times when you're going to wish you had more. All you can really do is buy what you can afford that will meet your needs now and hopefully a little into the future, don't become paralyzed with indecision based on what you might need some day. It is only very recently that we even had the luxury to think about this, 20 years ago a 100MHz DSO would have been well out of budget of all but the most serious hobbyists. When I got into electronics as a kid even a 20MHz analog scope was something I could only dream of owning.

One thing to remember with these budget scopes is they hold their value very well. Look on ebay for sold examples of a scope like the DS1054z, not asking prices but actual sold items. You will find many used ones that sold for nearly as much or in some cases even more than it costs to buy a brand new one from a place like Tequipment. Whatever you buy, take good care of it, don't be careless and fry it or let it get all beat up. Save the box and all of the odds & ends that come with it and if you later decide you need to upgrade you can probably get back most of what you spent on it by selling it to someone else. This does not have to be a major life decision and long term commitment. You don't have to buy the scope today that you will use for the rest of your life.

[Lowkus]

While I'm pondering on this oscilloscope advise, I should probably order a couple of DMM's.  I'd like to support EEVBlog by buying the branded units, is there a good reason to choose one over the other in looking at the 121GW or the BM786?  Is it best to own two of the same model to have accurate comparison of the measurements, or better to get two different models for some reason?

[bdunham7]

Pictures of engineer's labs are often filled with tons of equipment, is it gear acquisition syndrome where they are buying new toys to use even though they could get by with what they have, or is it built up because they repeatedly have to buy faster/better/stronger gear that will match the increasing difficulty of their projects?

Both reasons apply.  It's not easy to equip yourself in anticipation of some need that you don't fully understand.  For example, if instead of PCMCIA you had a problem with an LVDS circuit, you might use $15K+ in probes plus an oscilloscope that costs as much as a nice car to scope it:

http://cdn.teledynelecroy.com/files/appnotes/lab1012.pdf

There are some basic things that you can get relatively affordably that will always be useful at almost any level--DMMs, AWGs, PSUs.  OTOH, Oscilloscopes and spectrum analyzers start getting very expensive once you move beyond the 'prosumer' level, which is one level above 'entry'.  Those are the sorts of things that some of us are perpetually scrounging for.

While I'm pondering on this oscilloscope advise, I should probably order a couple of DMM's.  I'd like to support EEVBlog by buying the branded units, is there a good reason to choose one over the other in looking at the 121GW or the BM786?  Is it best to own two of the same model to have accurate comparison of the measurements, or better to get two different models for some reason?

One of each, of course!  There's no particular reason to own two of the same model.  Having different ones just makes it more possible that one or the other will have a feature you need that the other lacks.  I see the 121GW is quite cheap today on Amazon.  The BM786 looks expensive, maybe wait for a deal.

[tautech]

While I'm pondering on this oscilloscope advise, I should probably order a couple of DMM's.  I'd like to support EEVBlog by buying the branded units, is there a good reason to choose one over the other in looking at the 121GW or the BM786?  Is it best to own two of the same model to have accurate comparison of the measurements, or better to get two different models for some reason?

Personally I would steer away from a 121 and get the BM235 and maybe the 786.

[Old Printer]

OP - Since you are not in a particular rush for a scope, I would hound Craigslist - OfferUp etc for one of the black case original AD1's. It will do 95% of what an AD2 will do and there were a lot of them sold to EE students for $99 back a few years before the program was cut. Once they hit ebay they are likely to get expensive, but CL & OU are a bit under the radar. I picked one up a couple years back for $50 on ebay. When you are not in a hurry, deals appear.

[rstofer]

I have both the 121GW and the BM235 versions and they are excellent.  I don't use them very often...  I also have a Fluke 189 that doesn't get much use.  And some others...

For me, those meters are 'clubby'.  They stand up pretty well but they are big and awkward when compared to a pocket size meter like the Aneng 8008 which is my preferred meter.  Besides, I can buy a bunch of 8008s for the cost of the Fluke.  Dave has done a review of the 8008.

I also have a couple of 'bench' meters that don't get much use.  They have the advantage of having a fixed place to park so size and weight doesn't become an issue.  Somehow, it is just too much effort to use these to verify a resistor value.  Or verify Vcc...

I am of the opinion that you need at least 3 DMMs and they need not be all the same.  I would certainly include the 8008 in the mix.

[james_s]

While I'm pondering on this oscilloscope advise, I should probably order a couple of DMM's.  I'd like to support EEVBlog by buying the branded units, is there a good reason to choose one over the other in looking at the 121GW or the BM786?  Is it best to own two of the same model to have accurate comparison of the measurements, or better to get two different models for some reason?

I hear a lot of people recommending multiple DMMs but personally there is one handheld meter that I use 99% of the time and then I have a bench meter that lives on my bench, and I have a few other random meters that have accumulated but I almost never use those. There have been times that I've used two meters at the same time but it has been very rare and I personally would not run out and buy more than one multimeter.

[rdl]

I have a Fluke 87-III but I don't recall turning it on since I got the Aneng 8008. I also have a RSR M9803R bench meter (rebranded Mastech) that gets used quite a bit. I like a bench meter because they can sit on a shelf out of the way and don't need batteries.

[rstofer]

While I'm pondering on this oscilloscope advise, I should probably order a couple of DMM's.  I'd like to support EEVBlog by buying the branded units, is there a good reason to choose one over the other in looking at the 121GW or the BM786?  Is it best to own two of the same model to have accurate comparison of the measurements, or better to get two different models for some reason?

I hear a lot of people recommending multiple DMMs but personally there is one handheld meter that I use 99% of the time and then I have a bench meter that lives on my bench, and I have a few other random meters that have accumulated but I almost never use those. There have been times that I've used two meters at the same time but it has been very rare and I personally would not run out and buy more than one multimeter.

I was thinking about educational projects.  I would find it handy to measure base current, collector current and Vce simultaneously if I were studying transistors.

Every day?  One meter seems adequate most of the time.

[wizard69]

If I was just starting out today a scope would not be high on my list.   This mainly due to getting by for a long time without.   There is a real need for many tools to get started and frankly if you can get a lot of functionality out of one product, an AD2, it can save a student a lot of money.   Which is why college students buy the unit.

What kind of tools would you recommend someone purchase before an oscilloscope?

I've been OTL for a few days so I read through the thread before coming back to this question.    You have gotten lots of good ideas and comments so I'm going to take a wider approach.    I'm assuming you are absolutely new to this so if not there are things you can self delete.   So think of this as somebody that wants to start at the very beginning, the equivalent of Electronics 100.

• The Instrumentation:
  
  A good multimeter DMM!  That means neither low end nor high end just a decent meter with a good display.
  
  A low end VOM.   I know in this digital world people might rebel at the idea but I look at a VOM as another way to learn concepts in electronics.
  
  A power supply.   I highly recommend a DIY fixed voltage unit using 3 terminal regulators.   This is part of the learning experience and can serve your interests for now.   The alternative is batteries or wall warts.
  
  
  
• The Works Space
  
  You will need a decent works space which means some sort of bench, ideally in a dedicated area.   Ideally that bench will have storage space either built in or adjacent to the bench.    You will also need a comfortable chair.
• The Lighting
  
  I have this separate from the work space because I see it as extremely important especially for repair.   This includes room or ambient lighting and task lighting.
• The "Tools"
  
  A soldering station / iron.
  
  A set of screwdrivers.
  
  Needle Nose pliers.
  
  Diagonal cutters.
  
  A Panavise.
  
  Test leads, patch cords.
  
  A breadboard (not a cheap one).
  
  A magnifier.
• Documentation
  
  This is so easy these days I only list it here for nostalgia.
• Texts
  
  Find NEETS {Navy Electricity and Electronics Training Series} if you want something free.
  
  Frankly I'm too old to suggest something new, as an introductory students text.   Hopefully somebody can give you a current title that is modern.
  
  For library fill out:  The Art of Electronics

[james_s]

For the multiple DMM situation if you want that there's the option of one good meter and a couple of cheapies. Even the $5 Harbor Freight meters that you can occasionally get for free are adequate for measuring voltage in low voltage circuits. I wouldn't use one on line voltage or electric car batteries or something but for hobby stuff they're fine. A comparable meter when I was a kid in the 80s would have been the equivalent of $100+, all I could afford back then was a basic analog VOM. It's amazing what you can get now.

[Old Printer]

I picked up an 8008 when they first came out, I think I paid $9 shipped. I really bought it just to see if it would actually show up, but it did, in a week, and became my go to meter on the bench. I just ordered a 2009 on AliExpress for $22, the best price I could find. They really are great little meters, and if someone says gee I wish I had a meter, you can had it to them and be a big shot for a few bucks