Are low/lower cost USB Oscilloscope's any good?
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From: news.valornet.com on 13 Dec 2006 14:27 Hi, I am just trying to mess around with electronics stuff, and I don't know too much, but I've put a circuit or two together with help from this forum and others. I've got a fluke DMM and clampmeter, but I'd really like to be able to scope some stuff sometimes. I just don't know if I could part with the money for a portable scope like a fluke 123 however just for playing around. I have some questions and appreciate any suggestions for what might be good: 1. Do most scopes have decent voltage input on them? For example, can you hook most of them up to line power (120vac or 240vac)? I am assuming the fluke can do this no sweat, but I don't know. 2. I also see a bunch of references to X10 probes. Are these used to reduce the voltage to something a scope can use, for example 240VAC --> 24VAC ? 3. Do you have any recommendations for a scope that works on a notebook that is relatively low cost that has decent features (keep in mind I have no idea what features you would want in a scope). I would even consider some of these scopes that are free based ones that work with a sound card, but my question is, what type of voltage input can you get with a microphone jack??? Thanks! Alan
From: Joel Kolstad on 13 Dec 2006 14:41 "news.valornet.com" <nospam38925(a)forme.com> wrote in message news:8ed43$45805409$d861a4c3$27629(a)ALLTEL.NET... > I just don't know if I could part with the money for a portable scope like a > fluke 123 however just for playing around. I wouldn't. You're much better off getting something cheap, playing with it for awhile, and then -- if you're motivated to go further -- getting the high-end Fluke stuff. > 1. Do most scopes have decent voltage input on them? For example, can you > hook most of them up to line power (120vac or 240vac)? No! It depends a lot on the scope, of course, but most don't want to see more than "some tens of volts" directly. You can, of course, easily build yourself "high voltage" probe that are just resistive dividers. > 2. I also see a bunch of references to X10 probes. Are these used to > reduce the voltage to something a scope can use, for example 240VAC --> > 24VAC ? x10 probes are actually used more to not load down the circuit being probe than to bring 240V->24V. This is done because heavy loading kills a circuit's frequency response -- the idea probe would have *no* influence on what was being measured, but a good approximation of this becomes difficult to do (especially *inexpensively*) when you start getting into the hundred MHz and up ballpark. > 3. Do you have any recommendations for a scope that works on a notebook > that is relatively low cost that has decent features (keep in mind I have no > idea what features you would want in a scope). I've been impressed with these guys: http://www.cleverscope.com/ -- they seem to have a solid understanding of what terms like "noise" and "jitter" mean, unlike many of the cheap scopes out there. These guys: http://www.bitscope.com/ ...are popular (they're one of the original players), but their performance seems a little lacking these days. In their older models, you couldn't sample both channels simultaneously (well, "chopped") without decimating the sampling rather either... uggh! > I would even consider some of these scopes that are free based ones that > work with a sound card, but my question is, what type of voltage input can > you get with a microphone jack??? I'd guess something under a voltage. ---Joel
From: Jan Panteltje on 13 Dec 2006 14:43 On a sunny day (Wed, 13 Dec 2006 13:27:01 -0600) it happened "news.valornet.com" <nospam38925(a)forme.com> wrote in <8ed43$45805409$d861a4c3$27629(a)ALLTEL.NET>: >Hi, > >I am just trying to mess around with electronics stuff, and I don't know too >much, but I've put a circuit or two together with help from this forum and >others. I've got a fluke DMM and clampmeter, but I'd really like to be able >to scope some stuff sometimes. I just don't know if I could part with the >money for a portable scope like a fluke 123 however just for playing around. >I have some questions and appreciate any suggestions for what might be good: > >1. Do most scopes have decent voltage input on them? For example, can you >hook most of them up to line power (120vac or 240vac)? No, that will likely destry teh scope. >I am assuming the >fluke can do this no sweat, but I don't know. I think not. >2. I also see a bunch of references to X10 probes. Are these used to >reduce the voltage to something a scope can use, for example 240VAC --> >24VAC ? If the range is 20V / division with 8 divisions, then that scope _should_ be able to handle 160Vpp at least... But a 24V sinewave is already 2 x 24 x sqrt(2) = 68V pp, so watch out, and think in peak peak values always. >3. Do you have any recommendations for a scope that works on a notebook >that is relatively low cost that has decent features (keep in mind I have no >idea what features you would want in a scope). >I would even consider some of these scopes that are free based ones that >work with a sound card, but my question is, what type of voltage input can >you get with a microphone jack??? You could make your own, for less then a new digital scope, http://www.fpga4fun.com/digitalscope.html over to others to recommend stuff. Or you could get a cheap analog one from ebay. Forget the sound card scopes other then for monitoring sound....
From: Hal Murray on 13 Dec 2006 15:04 >I've been impressed with these guys: http://www.cleverscope.com/ -- they seem >to have a solid understanding of what terms like "noise" and "jitter" mean, >unlike many of the cheap scopes out there. A friend has one. He's very happy with it. One of the advantages of a PC based scope is that it doesn't take up much room on your desktop. -- These are my opinions, not necessarily my employer's. I hate spam.
From: Joerg on 13 Dec 2006 15:07
Hal Murray wrote: >>I've been impressed with these guys: http://www.cleverscope.com/ -- they seem >>to have a solid understanding of what terms like "noise" and "jitter" mean, >>unlike many of the cheap scopes out there. > > > A friend has one. He's very happy with it. > > One of the advantages of a PC based scope is that it doesn't take > up much room on your desktop. > But why are they so slow? At least the ones I have seen were. We designed 400MSPS converter boards even back in the late 80's and early 90's. It ain't rocket science. -- Regards, Joerg http://www.analogconsultants.com |