Author Topic: first o-scope  (Read 6615 times)

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Offline HooRide

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first o-scope
« on: April 11, 2011, 08:33:56 pm »
I've been tinkering with electronics since my early teens and recently seriously questioned myself why, now in my mid 20's, I hadn't purchased an oscilloscope yet.

I have a friend with a Rigol and have seen all the positive attention it gets all over the net but....I have the 'buy it once' mentality and those new Agilent scopes look simply amazing.


Even with money to 'kick around,' would it be foolish for me to essentially blindly buy a $4k scope as my first one? (100MHz or 200MHz 4ch w/logic analyzer)

I currently make projects with BASIC stamps and Audrino boards but want to get into more complex FPGAs ect.
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Offline neoone

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Re: first o-scope
« Reply #1 on: April 11, 2011, 08:53:28 pm »
buy cheaper one like Rigol and by the time it's not enough for your new designs Agilent will be probably cheaper if you really need it. And you can always sell Rigol if it hurts that you have spent 350$ for it but when compared to 4k$... well you know what I mean. I'm into electronics for about 15 years now (about 4 professionally) and my first "real" scope is Rigol which I bought few months ago. It is much easier with scope but I managed to live without it for a long time so I personally don't think that 4k$ scope is a must have for most purposes even for a professional electronic engineer. Of course I don't underestimate it's value and if I had enough money to spend I would gladly buy Agilent as my friend will probably do in the nearest future after he sells his Tectronix scope (as I said selling is always an option). 
« Last Edit: April 11, 2011, 09:03:30 pm by neoone »
 

Offline Wim_L

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Re: first o-scope
« Reply #2 on: April 11, 2011, 10:20:31 pm »
Difficult one. As a rule of thumb: buy the best you can afford. More bandwith, more memory, more features, bigger screen... All are good, and will make it easier to do whatever you want to be doing.

On the other hand, one has to balance priorities. Is it just for a hobby? How much cash do you want to throw at the hobby? If you spend all you can afford on a scope, how will you pay for the soldering station, function generator, programmer, multimeter,... Also take into account that while more bandwifth is always better, using it effectively mean you'll be running into the limits of passive probes. As a general rule, a 100 MHz (approximately) scope is a good general purpose troubleshooting device. Making use of faster scopes without loading the circuit excessively may often require active probes that can be as expensive as the scope itself.

When I was in your situation a while back, I picked up a Hameg 1508-2. The Agilent scopes weren't around yet, and the Hameg had a very compelling feature set: both analog and digital scope in one, high quality screen, lots of memory, two analog and two logic channels (with some logic triggering), no annoying noisy fan. However, it did cost me a lot more (about 2000 EUR) than a somewhat weaker Rigol of similar bandwidth. I made the decision after a brief demo of a Rigol (don't recall exact model, I think it was a 2ch, 100 MHz, 1Mpoint memory), Tek 2000B series, and the Hameg. It was a compromise solution, but overall I have few complaints about it and found it was worth the extra cost compared to a Rigol. Best would be if you could try a scope at a shop or a friend who has one already. Technical specifications don't say it all, ergonomics (the feel of the instrument) matters a lot for a device you'll be using often.
 

Offline HooRide

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Re: first o-scope
« Reply #3 on: April 11, 2011, 10:55:23 pm »
buy cheaper one like Rigol and by the time it's not enough for your new designs Agilent will be probably cheaper if you really need it. And you can always sell Rigol if it hurts that you have spent 350$ for it but when compared to 4k$... well you know what I mean. I'm into electronics for about 15 years now (about 4 professionally) and my first "real" scope is Rigol which I bought few months ago. It is much easier with scope but I managed to live without it for a long time so I personally don't think that 4k$ scope is a must have for most purposes even for a professional electronic engineer. Of course I don't underestimate it's value and if I had enough money to spend I would gladly buy Agilent as my friend will probably do in the nearest future after he sells his Tectronix scope (as I said selling is always an option). 

Thanks for your response! I wish it were that clear-cut; a comparable Rigol is $1200. If it were truly only $350, it would be a pretty easy decision.


Difficult one. As a rule of thumb: buy the best you can afford. More bandwith, more memory, more features, bigger screen... All are good, and will make it easier to do whatever you want to be doing.

On the other hand, one has to balance priorities. Is it just for a hobby? How much cash do you want to throw at the hobby? If you spend all you can afford on a scope, how will you pay for the soldering station, function generator, programmer, multimeter,... Also take into account that while more bandwifth is always better, using it effectively mean you'll be running into the limits of passive probes. As a general rule, a 100 MHz (approximately) scope is a good general purpose troubleshooting device. Making use of faster scopes without loading the circuit excessively may often require active probes that can be as expensive as the scope itself.

When I was in your situation a while back, I picked up a Hameg 1508-2. The Agilent scopes weren't around yet, and the Hameg had a very compelling feature set: both analog and digital scope in one, high quality screen, lots of memory, two analog and two logic channels (with some logic triggering), no annoying noisy fan. However, it did cost me a lot more (about 2000 EUR) than a somewhat weaker Rigol of similar bandwidth. I made the decision after a brief demo of a Rigol (don't recall exact model, I think it was a 2ch, 100 MHz, 1Mpoint memory), Tek 2000B series, and the Hameg. It was a compromise solution, but overall I have few complaints about it and found it was worth the extra cost compared to a Rigol. Best would be if you could try a scope at a shop or a friend who has one already. Technical specifications don't say it all, ergonomics (the feel of the instrument) matters a lot for a device you'll be using often.

That's a great question, it's more than just a hobby, I plan to continue my education in the field and turn it into a career so I see it more as throwing cash into education. Also, you make a great point about ergonomics and feel of a tool. When I jumped from a Radio Shack pencil iron to a Weller station soldering went from being tedious to actually kinda fun. Same idea when I upgraded DMMs; I didn't know what I was missing out on until I upgraded. That might explain why I am considering getting a nicer o-scope to start with. As for a function generator, I was going to use the one built-in to the Agilent o-scope (if I got it), seems pretty decent. Thanks to Dave's blog videos, I feel like I don't really have to go out and find a place to demo either the Rigol or Agilent, he's done a fantastic job for us all.
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Online EEVblog

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Re: first o-scope
« Reply #4 on: April 12, 2011, 01:00:31 am »
Yeah, as Wim_L said.
It's a matter of weighing up. $4K buys you a pretty awesome complete lab setup many would be envious of, so spending it all on one scope when you don't have the other stuff is probably not the best decision.
Nothing wrong with buying say the $1200 Agilent and upgrading later as needed though. No one will ever say that's a bad investment by any stretch compared with the Rigol, if you have the money and like buying quality tools.

On the "feel" side, it's not surprising the Agilent beats the Rigol hands down. The bigger and better screen, the controls, the operation, the response time etc. But you'd expect that for 3 times the price of course. I like the Rigol and still think it's superb value for money, but now that I have both, the Rigol feels much cheaper than it used to...

Dave.
« Last Edit: April 12, 2011, 01:04:53 am by EEVblog »
 

Online Mechatrommer

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Re: first o-scope
« Reply #5 on: April 12, 2011, 02:21:53 am »
buy the best you can get. but make sure you will afford to buy another gear too. if i have 4K for a scope and another 1K to spare for others, i will find the best 4K scope around. keep upgrading is a waste of money.
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Offline hacklordsniper

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Re: first o-scope
« Reply #6 on: April 12, 2011, 05:31:00 am »
Generally i was in same situation sometimes but i bought always the top equipment and with time you will not regret if you plan to learn and develop your knowledge.

But beware selling a 300 $ Rigol if you wont need it is very easy and probably you will loose 20 $ or nothing. I'm just expecting my Infinivision and with few options added and VAT its just close to 8k$, selling that second hand would probably get 2500 k$ maximally.

Also its good to have a 300 $ Rigol for probing high voltage circuits if you work on it...
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Offline FreeThinker

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Re: first o-scope
« Reply #7 on: April 17, 2011, 01:38:04 pm »
Just my 2 cents but I take the view that you should only buy what you NEED and does the job in hand. A lot of my gear is 20 or 30 yrs old and second hand (at least) it does the job and is cost effective. Ebay is a great source of used gear and unless you need professional standards of compliance do a great job. A shiney new Rigol is nice but pales when compared with a tek or Agilent, however unless you are using the agilent every day for hours on end can you justify the cost difference? Assess your NEEDS and look for the most cost effective solution.
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Offline tekfan

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Re: first o-scope
« Reply #8 on: April 17, 2011, 08:27:22 pm »
Just my 2 cents but I take the view that you should only buy what you NEED and does the job in hand. A lot of my gear is 20 or 30 yrs old and second hand (at least) it does the job and is cost effective. Ebay is a great source of used gear and unless you need professional standards of compliance do a great job. A shiney new Rigol is nice but pales when compared with a tek or Agilent, however unless you are using the agilent every day for hours on end can you justify the cost difference? Assess your NEEDS and look for the most cost effective solution.

Same goes here. You can even get standards on ebay, although there are no calibration certificates.

I don't think a beginner would want to spend 4k on a scope.This is why second hand analog scopes are great. Cheap, useful and you might even learn how an oscilloscope works. But then again if you're into digital the Rigol is probably the best answer.
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Offline shadowless

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Re: first o-scope
« Reply #9 on: April 24, 2011, 11:05:52 pm »
I am in a similar kind of situation. I have considered the used analogue scope but the good working ones makes Rigol sound like a decent deal while the dubious as-is ones will probably make you into a scope repairman.

The used digital tek scope are are not much value when the new models are just a bit more now with the lower scope price. Getting an Agilent vs Rigol is like getting an ipad vs a epad.

My purpose of the scope at the moment is to tune 2 pwm signals phasing to get the proper slight overlap and a 2 channel scope will be useful.  I might be working on circuits with 3 phases, can that be tune with a 2 channel scope? 

What is the consideration if one should get a 2 channel or 4 channel scope?  Is there a value Rigol type 4 channel scope around?
 

Offline francisjoe45

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Re: first o-scope
« Reply #10 on: April 25, 2011, 02:01:36 pm »
I too am planning to buy my first o-scope this week, I will be using it to design a BLDC motor controller.

Would a Rigol 50Mhz DS1052E be enough for me to be able to see the Back EMF (BEMF) voltage coming from a BLDC motor? I am also educating myself on digital signal processing and it is very hard to learn "blind" without an oscilloscope. Would the rigol DS1052E be somewhat useful even on basic digital signal processing?
 

Offline Tony R

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Re: first o-scope
« Reply #11 on: April 25, 2011, 03:40:03 pm »
I would say to get an analog one, you learn a lot more that way, digital scopes are great and given the option i would use one hands down. However you can probably get a analog for 20 bucks... i did off Craigslist list...

point being a digital scope is nice, you can get alot of information from it very quickly, but you can just tell some things from an analog scope that you cant from digital ones. i fully support getting both, but the rigol should do you more then good for years to come.
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Offline francisjoe45

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Re: first o-scope
« Reply #12 on: April 25, 2011, 05:34:19 pm »
thanks for the advice Tony R, I agree on getting an analog oscilloscope, as a matter of fact, that was my first choice. However, here in the Philippines, used analog scopes are scarce and the brand new ones are more expensive than the Rigol DS1052E. How I wish I could get an o-scope for 20 to 30 bucks off the craigslist (another thing we that we don't have here). We do have a big community of electronics enthusiasts here however since the demand for o-scopes here is so little, they are so much more expensive.
« Last Edit: April 25, 2011, 05:36:26 pm by francisjoe45 »
 

Offline saturation

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Re: first o-scope
« Reply #13 on: April 25, 2011, 06:13:56 pm »
If you get a working scope for $20 its certainly worth it even if one didn't need it.  
If you have no task to complete but have the scope as another test tool in the bench to use ad lib, its perfect.

But if you need a scope for a particular purpose, keep in mind used can die on you any time depending on its age or it may not work right in subtle ways unless you performance test it.  Its best if you know the prior owner took good care of it.  Its becomes a question of risk, can you complete your coursework or project on time before the test tool fails?  Will the time delay matter if you now put your project on hold to repair the scope?  Are the parts you need easy to locate?  Are you capable of doing the repairs?  If you need critical measurements, is its timebase and vertical amp still in spec?

With a new scope, those aren't issues as its generally returnable if it wasn't damaged by incorrect use.
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Offline torch

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Re: first o-scope
« Reply #14 on: April 30, 2011, 03:45:38 pm »
Would a Rigol 50Mhz DS1052E be enough for me to be able to see the Back EMF (BEMF) voltage coming from a BLDC motor? I am also educating myself on digital signal processing and it is very hard to learn "blind" without an oscilloscope. Would the rigol DS1052E be somewhat useful even on basic digital signal processing?

I can't say for sure about brushless, but I've used mine to diagnose and repair permanent magnet 220vDC motor controllers (PWM and SCR types). It's particularly useful in determining the absolute voltage peaks and duty cycles. (it was also quite educational to see the differences in inductive and resistive loading, the differences in waveform between PWM and SCR, etc., but I digress).

It should be fine for something really basic, like UART serial communications and maybe even USB if you do the 100MHz hack, but the DS1052E does not come with a logic analyzer. The DS1102D does, but is considerably more money.
 

Offline francisjoe45

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Re: first o-scope
« Reply #15 on: May 04, 2011, 04:10:21 pm »
Thanks for the reply, I bought a new Rigol DS1052E anyway, it was on sale for about $380 and nothing can really beat it at this price, even the 20Mhz OWON Oscilloscope is more expensive here in my country because of all the taxes.

I'd say that the Rigol really is good value for money for a "first-time" oscilloscope.
 


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