Hi,

I am currenting looking for an affordable digital oscilloscope for my home electronics lab. I have been looking around and it appears I will be spending around $1000 - $2000 in total (oscilliscop + accessories).

Some of the features I am looking for are:
2 or more channels.
Isolated channels cappable of at least +/- 700 V Common mode range.
At least 25 MHz Bandwidth.
Able to record at high sampling rate. I use a fluke at work that has a high sampling rate in scope mode but a very poor rate in record mode. So that is something I am looking out for.
A long recording memory is desired, like around a million samples, but I will probably have to settle for around 10,000 samples based on what I am seeing.

As for the isolated channels I will probably have to get a scope with grounded channels and use differential probes. I would appreciate any recommendations on the probes as they are currently looking like they will be the most expensive part.

I would like a benchtop or handheld oscilloscope but I am willing to settle for a PC one. One setup I am considering is a PicoScope 2205 with TA041, TA057 probes.

Some of the brands I have been looking at are Owon, Instek and Rigol.
I have been looking at www.tequipment.net, they seem to have good prices and stock. Does anyone have any experience buying from them or recommend somewhere else?

Basically I am looking to hear from anyone that has any comments or testimonials from there own purchases of related oscilliscopes or brands.

Thanks,
Dan

 

Isolated channels cappable of at least +/- 700 V Common mode range.

You may have a hard time with that spec.

 

Hi Dan,
Welcome to AAC.
I'm pretty "old school" myself. I have a couple of linear scopes, a Hitachi V-660 and an old Tektronix 2215, both dual-trace 60MHz scopes, with some 100MHz probes that I bought on an auction site a few years back; 8 for $80. The probes are certainly not stellar quality, but they do work.

It's hard to go wrong with an older Tektronix scope; you can actually fix them if something breaks. With the digital scopes, you might as well throw them away and buy a new one rather than pay to have them fixed. It is hard to beat a good old-fashioned linear scope for accurate waveform depiction - but you have to be able to understand what you are looking at.

I don't understand why you would need to acquire a million samples. Is your data stream that long? Would you live long enough to analyze it all?

 

I have been looking at www.tequipment.net, they seem to have good prices and stock. Does anyone have any experience buying from them or recommend somewhere else?

I bought a OWON PDS5022s from them. No problems, fast service. It was delivered to Baltimore, Maryland in two days with their standard shipping.

 

Here are some differential amplifiers that might suit your needs. I got the CT2593-2 and it's suitable for my needs.

I can't comment on the various brands you mentioned, since I haven't used them. I have a Philips 25 MHz analog scope I bought back in the 1970's and it still works great -- it's a good scope and the manual has full troubleshooting information in case something needs to be fixed. About 8 years ago I bought a used HP 54601B scope on ebay and I really like it, as I've never needed a manual to figure out how to use it.

I also have a B&K 2534 on loan. It's an $800 60 MHz digital scope and I think it's a pretty good scope for the price. Neither of my digital scopes trigger quite as well as the analog scope (and I've looked at 60 MHz signals with the analog scope even though it's "only" a 25 MHz scope).

Buying a scope is a lot like buying a machine tool -- most people don't plan on spending any money on "tooling", when in fact you should probably allow around a quarter to third of your expenditure for "tooling". By tooling, I mean things like scope probes, the differential amplifier, BNC cables, RF adapters, etc. For example, I use a number of dual male banana plug to female BNC adapters and those can cost about $5 each. Here's an adapter kit for $150 that could save your bacon some day. I think you're smart to be budgeting money for the accessories too!

You don't explain why you want a scope with a deep trace. Personally, I think that may be much more than you need for a home scope. The B&K scope digitizes 4000 points in a trace and that's entirely suitable for my needs. Of course, if you need deep traces, the scopes are available, but you're going to pay more money for them.

Personally, I would never want a USB scope for the bench -- I find the all-in-one scope's display and knobs just too compelling and familiar. If I was doing work in the field with a laptop, that would be a different thing.

 

2 or more channels.
Isolated channels cappable of at least +/- 700 V Common mode range.
At least 25 MHz Bandwidth.
Able to record at high sampling rate. I use a fluke at work that has a high sampling rate in scope mode but a very poor rate in record mode. So that is something I am looking out for.
A long recording memory is desired, like around a million samples, but I will probably have to settle for around 10,000 samples based on what I am seeing.

The only currently available scope I am aware of that has isolated inputs is the TPS2000 series from Tek, but it only has 2500 samples.

You will undoubtedly need to use a separate differential amp. The ones someonesdad linked to look like the Yokogawa units rebadged.

The Rigol DS1000E series:

(http://cgi.ebay.com/Rigol-Oscillosc...ItemQQptZBI_Oscilloscopes?hash=item3efb96a226)

have a quite long trace memory of 1 million points single channel, or 512k dual channel. This long memory is only available at a slightly reduced sample rate of 500MSa, but it might well meet your needs.

 

My main field scope is the Pico 5203, it's alright.
250MHz is overkill for home work and at times narrow for job stuff
if you want a review and are considering it, let me know.
http://www.picotech.com/picoscope5200-specifications.html

But I must agree with the Sgt.
My go-to scope for the last 30 years is the 7704 Tektronix.
Still to this day the plug-ins are available and at dirt cheap prices.
here are a sample of a few of them.
http://www.mjs-electronics.se/images/Tek/5-7000/5-7000.htm


pictured here is my "buddy".
I wouldn't be without it.
this scope and a dozen different plug-ins do the bulk of my home lab work.
It doesn't store but I have an old Hewlett Packard 1741A on the bench also that meets rudimentary needs with auto-store.

in fact, after all these years of buying old scopes and rebuilding them for resale, rarely do I get stuck with a scope that, when received, wasn't a steal for the price paid.

they are just so darn cheap.

 

My THS710A 60mhz has isolated inputs (voltage dependant on probe but its up to 1000v) but its also battery powered. It's almost 20 years old but works quite nice, only thing I miss is a usb connect instead of a rs232.

I used GW DSO scopes at work and they were easy to use and reliable as well.

I have to admit, these are really the only two scopes I've used to any extent.

 

Thanks for your replies.

I actually already have some analog scopes. I have some old Tektronix and B and K scopes. They have been suitable for many things but have been coming up short on some of my latest projects. I can't record or archive data. Or use computer software to perform operations on the data.

Some of the desired uses for this scope are:
*Analyze power electronic circuits
*Recording files for documentation and collaboration
*Use realtime analysis tools (I probably won't get much of these for price of scopes I am looking at)
*Export the scope data to a format that can be analyzed by other programs, such as CSV
*Analyze circuits with complicated feedback algorithms, this is the main reason I wanted a long record memory. I find it much easier to analyze these circuits with a much bigger picture of whats happening. Although its not critical and I might not get the long record memory.


I have been looking at the Rigol scopes a little more closely. They look good on paper. I think they are a chinese company. I have had mixed experience with these cheap chinese tools. But if I do my research I usually don't have much issues. I got a cheap knock off rework soldering station that has just worked great.
Has anyone used Rigol as well as Owon or Instek scopes? Just curious how they compare.


It is currently looking like the probes will cost the most. I need two and at more than $300 a piece they might cost more than the scope I'll get.
Does anyone have any recommendations for differential probes? I keep on finding these generic probes on different websites that cost around $300 for 700V isolation with 25 MHz bandwidth.
Here are some I am considering buying:
http://www.tequipment.net/TPIADF25A.asp

Any comments on them?