My old Philips analogue oscilloscope went broke and I decided to purchase a digital oscilloscope.
Because I do not want to purchase again a hardware one I decided to give a software oscilloscope a go.
Some internet browsing gave me a scope from the Picotech company as a good candidate.
Now I hasitate which one to buy: the Picoscope 2204A or the Picoscope 2205A.
The 2204A is the cheapest, the 2205A costs substantially more.
I only need the scope to use it measuring LF amplifiers. Because I also have to detect if an amplifier is
oscillating or not, which oscillation frequencies can be in the order of a few MHz or so, perhaps a 10MHz
bandwidth (= 2204A) is more than enough?
Or shall I be on the safe side and purchace the 20MHz (= 2205A) oscilloscope?
Because I do not want to purchase again a hardware one I decided to give a software oscilloscope a go.
Some internet browsing gave me a scope from the Picotech company as a good candidate.
Now I hasitate which one to buy: the Picoscope 2204A or the Picoscope 2205A.
The 2204A is the cheapest, the 2205A costs substantially more.
I only need the scope to use it measuring LF amplifiers. Because I also have to detect if an amplifier is
oscillating or not, which oscillation frequencies can be in the order of a few MHz or so, perhaps a 10MHz
bandwidth (= 2204A) is more than enough?
Or shall I be on the safe side and purchace the 20MHz (= 2205A) oscilloscope?
For 10MHz you really need at least 100MHz sampling rate. Even that would only give you 10 points per cycle. So perhaps a 1GHz sampling rate would be better ?
While you only want to look at audio an ability to see high frequency oscillation could be useful.
One disadvantage of a PC scope is that the PC is tied to ground so you cant float the ground of the scope. You could get around that by floating your circuit using a mains isolation transformer or just leave your circuit floating.
While you only want to look at audio an ability to see high frequency oscillation could be useful.
One disadvantage of a PC scope is that the PC is tied to ground so you cant float the ground of the scope. You could get around that by floating your circuit using a mains isolation transformer or just leave your circuit floating.
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@nigelwright:
"One disadvantage of a PC scope is that the PC is tied to ground so you cant float the ground of the scope. You could get around that by floating your circuit using a mains isolation transformer or just leave your circuit floating."
I was aware of that and I have an isolation transformer (variac) available to us it in case of...
@Black_Chicken:
Thanks for sharing your experience with the 2205A.
I think I will purchase this type.
"One disadvantage of a PC scope is that the PC is tied to ground so you cant float the ground of the scope. You could get around that by floating your circuit using a mains isolation transformer or just leave your circuit floating."
I was aware of that and I have an isolation transformer (variac) available to us it in case of...
@Black_Chicken:
Thanks for sharing your experience with the 2205A.
I think I will purchase this type.
Hello,
In this price range, you can also look for the Analog Discovery from Digilent (159$ if student otherwise 259$).
It offer much more functionality : 14bits vertical resolution, differential inputs, 30MHz bandwidth,
2 channels arbitrary waveform generator, 16 channels logic analyzer // Pattern generator and much more...
I must say that it's the first USB instruments i own that have a very well done software.
There is much very well implemented function, a great value for money.
More infos about it here: Analog Discovery - USB Oscilloscope, Logic Analyzer And More
Frex
In this price range, you can also look for the Analog Discovery from Digilent (159$ if student otherwise 259$).
It offer much more functionality : 14bits vertical resolution, differential inputs, 30MHz bandwidth,
2 channels arbitrary waveform generator, 16 channels logic analyzer // Pattern generator and much more...
I must say that it's the first USB instruments i own that have a very well done software.
There is much very well implemented function, a great value for money.
More infos about it here: Analog Discovery - USB Oscilloscope, Logic Analyzer And More
Frex
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The Picoscope software is also very good. They are less functional than the Analog Discovery but more focused on specific oscilloscope tasks. none of the other USB scopes I have tried were worth the time to set up. I'm hoping the QA101 software gets better but its not there yet. I can use both the ver5 and ver6 software with the newer Picoscopes and in some ways I prefer the ver5. it also works with the 15 year old ADC200/100 I have. That's more than I can say for most PC based instruments (including National Instrument$$).
The Digilent is an absolute awesome piece of equipment. I've mounted it in a small case with BNC connectors for a little more robustness.
The network analyzer functionality for running frequency response is worth the price by itself. Throw in full function dual waveform generators, 2 channel decent speed scope, data logger, etc and its incredible. As said, the software and documentation is top notch too.
A Variac is NOT isolated, it is a variable autotransformer, with a single winding and a wiper.
https://cdn.instructables.com/FGP/ZIE5/HRI96Y43/FGPZIE5HRI96Y43.LARGE.gif
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Well, I call it a variac, which was a common name for an ISOLATED transformer which second winding is equipped
with a wiper. The one I am using and NOT a so called "auto transformer" with just one winding with a tap wiper and indeed is not isolated from the mains.
I bought the 2205 after my analog died last year. It's ok for troubleshooting. You need 1:10 probes since max input range is +-20Vp.
They have some annoying software features. Most annoying: When zooming the grids are random. There's no way of setting grids or zoom at fixed numbers. I asked them about it at Electronica last year and the dude said the software boss doesnt think it important even tho many people have mentioned it. It really is annoying enough that we do not buy them at my work. (I did accuire 5444B on sale, but seldom use it b/c of that very reason).
The other thing is for Picoscope V/div is the entire screen, not divisinos on the grids. So 2V/div is +2V at top of screen and -2V at the bottom. It's a little thing, but just stupid, and it annoys me along with the other thing I mentioned.
What really annoys me about Pico is the fact that they allow an idiot software man to keep those stupid features...
Ok back to 2205. The function gen is digital... I mean it really is step by step with almost no filtering. It's has ok resolutiono at max amplitude, but as you turn down the level the waveforms become staircases. So I use it at max and have a potmeter in between.
But hey you get what u pay for, and for that price they are ok for hobby use.
With the 8bit resolution I quickly decided to get another analog scope. Found refurbished ones on ebay from the US for 100USD, and shipping wasnt too bad, 30bucks or so. MUCH better than ten picoscopes IMHO.
They have some annoying software features. Most annoying: When zooming the grids are random. There's no way of setting grids or zoom at fixed numbers. I asked them about it at Electronica last year and the dude said the software boss doesnt think it important even tho many people have mentioned it. It really is annoying enough that we do not buy them at my work. (I did accuire 5444B on sale, but seldom use it b/c of that very reason).
The other thing is for Picoscope V/div is the entire screen, not divisinos on the grids. So 2V/div is +2V at top of screen and -2V at the bottom. It's a little thing, but just stupid, and it annoys me along with the other thing I mentioned.
What really annoys me about Pico is the fact that they allow an idiot software man to keep those stupid features...
Ok back to 2205. The function gen is digital... I mean it really is step by step with almost no filtering. It's has ok resolutiono at max amplitude, but as you turn down the level the waveforms become staircases. So I use it at max and have a potmeter in between.
But hey you get what u pay for, and for that price they are ok for hobby use.
With the 8bit resolution I quickly decided to get another analog scope. Found refurbished ones on ebay from the US for 100USD, and shipping wasnt too bad, 30bucks or so. MUCH better than ten picoscopes IMHO.
Can you tell us who made the transformer you have? I have not been able to find a vendor who make variable transformers with isolated windings. Every US vendor and the Chinese vendors I have contacted do not. They all suggest adding a seperate transformer.
I have a Picoscope 3206 and I just fired it up after your comments. Ver 6 software is more confusing to use especially with its 32 screens. But I seemed to get the hang of it pretty quickly. The spectrum analyzer is quite good and the measurements supported are very useful. I would admit it won't replace my other scopes. PC scopes are cumbersome for troubleshooting. (I revert to my Tek 7854 for real troubleshooting but its genuinely big.) However you can troubleshoot with a Picoscope and you can collect lots of data if you need to.
The vertical scaling sort of makes sense once you realize the range number is the max usable signal peaks. Horizontal is less obvious but its related the the sample rate, memory depth, update rate and a lot of other stuff that's distracting when all you want is a waveform. Tek has that down on their digital scopes, way better than the China variations, but for a price.
I designed my own USB scope.
It looks pretty much like a normal oscilloscope on the screen.
You can move traces left/right and up/down.
It has a trigger function off voltage, negative going, positive going or free trigger.
It also displays an FFT of signal on same screen as oscilloscope.
It has measuring pointers for time and voltage between two points.
It has 7 time bases and 8 voltage ranges.
Its only 1.4MSPS but is fine for audio work.
It looks pretty much like a normal oscilloscope on the screen.
You can move traces left/right and up/down.
It has a trigger function off voltage, negative going, positive going or free trigger.
It also displays an FFT of signal on same screen as oscilloscope.
It has measuring pointers for time and voltage between two points.
It has 7 time bases and 8 voltage ranges.
Its only 1.4MSPS but is fine for audio work.
PicoScopes vs. Digilent AD
I can second most of the stuff, that has been said before.
The Analog Discovery is also a VERY useful tool, but IMHO it is more targeted to other applications than a Scope. The capabilities are pretty much endless, esp. when coding your own software and building your own hardware... For the use as a Sope there is the lack of a decent analog frontend, housing, BNC etc. The potential of the 14bit resolution is wasted most of the time.
The PicoScopes are "scopes", nothing else. The have a defined Input Impedance, switch-able ranges, asymmetric inputs targeted to 1Meg probes etc. The software is sometimes a little bit clumsy. But hey, it also took a me a learning curve of several months to get used to the work flow of the LeCroy user interface. I started with a 2205A and later on upgraded to a higher resolution higher BW model for personal bench use. For me this is as near as you can get to a professional digital Oscilloscope for reasonable money. Since its PC-based, using a 24" touch-screen monitor (yes, I'm over-exaggerating a little bit
) is easily doable. For comparison, high-end Keysight and LeCroy Models advertise 12.1" (but the screen-utilisation of the LeCroys is better, Pico is wasting a little bit too much screen-area for my taste). Programming and automation is also straight forward.
Today, I use the 2CH 2205A more often than the "expensive 4CH" one and its a useful tool for general commissioning and debugging.
I can second most of the stuff, that has been said before.
The Analog Discovery is also a VERY useful tool, but IMHO it is more targeted to other applications than a Scope. The capabilities are pretty much endless, esp. when coding your own software and building your own hardware... For the use as a Sope there is the lack of a decent analog frontend, housing, BNC etc. The potential of the 14bit resolution is wasted most of the time.
The PicoScopes are "scopes", nothing else. The have a defined Input Impedance, switch-able ranges, asymmetric inputs targeted to 1Meg probes etc. The software is sometimes a little bit clumsy. But hey, it also took a me a learning curve of several months to get used to the work flow of the LeCroy user interface. I started with a 2205A and later on upgraded to a higher resolution higher BW model for personal bench use. For me this is as near as you can get to a professional digital Oscilloscope for reasonable money. Since its PC-based, using a 24" touch-screen monitor (yes, I'm over-exaggerating a little bit
) is easily doable. For comparison, high-end Keysight and LeCroy Models advertise 12.1" (but the screen-utilisation of the LeCroys is better, Pico is wasting a little bit too much screen-area for my taste). Programming and automation is also straight forward.Today, I use the 2CH 2205A more often than the "expensive 4CH" one and its a useful tool for general commissioning and debugging.
Thank you very much guys for all your comments.
Have just purchased the 2205A Picoscope and are now trying to find my way how to use it. To my (slight) disappointment
some of its features are not(yet) possible for me because my computer O.S. is a Linux distro and the software for it
is still a "beta" one which is not(yet) 100% compatible with the software when one is running under Windows.
(The only windows I have are in the walls of my house).
But until now I did not discover a thing which would force me to return that scope to the shop and get a money refund.
@ 1audio:
My Variac is a 3 amp variac from Philips which I purchased many years ago at some internet second hand electronics shop
(forgot what name it was sorry). It is the same one I was using at the company (Philips Netherlands) where I was working
for many years and has isolated windings.
Have just purchased the 2205A Picoscope and are now trying to find my way how to use it. To my (slight) disappointment
some of its features are not(yet) possible for me because my computer O.S. is a Linux distro and the software for it
is still a "beta" one which is not(yet) 100% compatible with the software when one is running under Windows.
(The only windows I have are in the walls of my house).
But until now I did not discover a thing which would force me to return that scope to the shop and get a money refund.
@ 1audio:
My Variac is a 3 amp variac from Philips which I purchased many years ago at some internet second hand electronics shop
(forgot what name it was sorry). It is the same one I was using at the company (Philips Netherlands) where I was working
for many years and has isolated windings.
Yupp, the linux support is not that nice. I am a linux user too and had high hopes, but PicoScope6 was crashing directly on Xubuntu 14.04 at the time I tried it. I still have a PC in my electronics-lab running MS Windows...
Personally, I think you cannot blame Pico because they support MS Win better than for other OS... working in the Industry means working with Microsoft operation systems. Naturally, Pico has to focus on Windows otherwise they would never get a foot on the ground in high volume orders (i.e. production tests environments etc).
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