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finding a cheap oscope
- Thread starter CWNW
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MikeHalloran
Mechanical
What signal do you wish to measure?
I personally don't care, but that's the first question you have to ask yourself.
Mike Halloran
Pembroke Pines, FL, USA
I personally don't care, but that's the first question you have to ask yourself.
Mike Halloran
Pembroke Pines, FL, USA
- Thread starter
- #3
electricpete
Electrical
If you're doing it in your garage and not at a job site, there are some cheap options that plug into your pc usb.
Even cheaper, there is freeware that records from your sound card if you are satisfied with 22khz sample rate and whatever the voltate limit there is.
Haven't tried any of them but thinking about them. At work we have a Fluke scopemeter 190 series. I think they go for $1000. Very handy and does just about all the data capture, storage, analysis and display functions you can think of right inside the unit.
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Even cheaper, there is freeware that records from your sound card if you are satisfied with 22khz sample rate and whatever the voltate limit there is.
Haven't tried any of them but thinking about them. At work we have a Fluke scopemeter 190 series. I think they go for $1000. Very handy and does just about all the data capture, storage, analysis and display functions you can think of right inside the unit.
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Skogsgurra
Electrical
I used to lug heavy Tek scopes around. Then, there were Fluke and TEK battery scopes with LCD. Very good. A lot better than the old ones. Then, there came Pico Technology with their Picoscopes and TiePie with their HSx units. Both companies only have USB data acquisition units that use the PC for HID and storage. My eperience is that the Picoscope is rather sensitive to short transient overvoltages (have already destroyed two 200 Mz units that both my LeCroy and TiePies survive).
The TiePie is my favourite. Four channels, 12 bit resolution is adequate for most work. The software is great. You can build filters and mathematical expressions using drag and drop right on the screen. Very good triggering and easy to set.
What limits the TiePie units is that they do not have the fastest sampling rate. At 50 MSa/s, I miss some of the details I can see with the LeCroy and the PicoScope.
There is another limitation with most USB units; they do not have the same sensitivity as you get with dedicated oscilloscopes. There may also be DC level issues.
Then, there are lots and lots of other USB units at low cost. Cost is so low that one could order a few different and see if they fill the bill.
Gunnar Englund
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
The TiePie is my favourite. Four channels, 12 bit resolution is adequate for most work. The software is great. You can build filters and mathematical expressions using drag and drop right on the screen. Very good triggering and easy to set.
What limits the TiePie units is that they do not have the fastest sampling rate. At 50 MSa/s, I miss some of the details I can see with the LeCroy and the PicoScope.
There is another limitation with most USB units; they do not have the same sensitivity as you get with dedicated oscilloscopes. There may also be DC level issues.
Then, there are lots and lots of other USB units at low cost. Cost is so low that one could order a few different and see if they fill the bill.
Gunnar Englund
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
eBay could be your friend, as could the surplus dealers. Buy from someone vaguely reputable though.
Personally I hate the Fluke / Phillips handheld scopemeters, or at least the older designs which I've been unfortunate enough to use. The user interface is dreadful and triggering is a gamble. The rival Tektronix products of the day were far far better. Of course Fluke may have improved their product immensely so if possible try before you buy.
If you don't need to transport it around then Tek's 465 or 475 are 100MHz and 200MHz analogue scopes respectively. Both look a little old fashioned but are good instruments and are common / cheap on the surplus market. If you want a digital scope then LeCroy make very nice instruments, as do HP / Agilent. Be careful with the specmanship which is rife in the DSO world, particularly for capturing one-off non-repetitive signals. Bandwidths and sample rates are not always what they claim to be.
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If we learn from our mistakes I'm getting a great education!
Personally I hate the Fluke / Phillips handheld scopemeters, or at least the older designs which I've been unfortunate enough to use. The user interface is dreadful and triggering is a gamble. The rival Tektronix products of the day were far far better. Of course Fluke may have improved their product immensely so if possible try before you buy.
If you don't need to transport it around then Tek's 465 or 475 are 100MHz and 200MHz analogue scopes respectively. Both look a little old fashioned but are good instruments and are common / cheap on the surplus market. If you want a digital scope then LeCroy make very nice instruments, as do HP / Agilent. Be careful with the specmanship which is rife in the DSO world, particularly for capturing one-off non-repetitive signals. Bandwidths and sample rates are not always what they claim to be.
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If we learn from our mistakes I'm getting a great education!
CharlieGill
Electrical
You can get a Tektronix 465 on ebay for under $200. It's a great scope for general use. I carried one for years in the field and now keep one in the shop for general use.
Charlie
Charlie
electricpete
Electrical
I agree with you Scotty the Fluke Scopemeter interface is not hugely friendly on the Fluke. I don't have a lot to compare it to other than 16-channel Yokogawa digital storage oscilloscope - much higher end but seems to have about the same level of clumsiness.
Actually I do have one frustration in my few encounters with the Scopemeter. I have been storing the data in my scope and using the embedded menu's to browse and analyse the data. I never spent enough time to figure out how to get it onto my pc (other than using my camera to photograph the waveforms on the screen). I think there is an attachment required to convert the pin connection on the meter into USB but we seem to have lost ours. If you buy one definitely get that attachment and don't lose it like we did.
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Eng-tips forums: The best place on the web for engineering discussions.
Actually I do have one frustration in my few encounters with the Scopemeter. I have been storing the data in my scope and using the embedded menu's to browse and analyse the data. I never spent enough time to figure out how to get it onto my pc (other than using my camera to photograph the waveforms on the screen). I think there is an attachment required to convert the pin connection on the meter into USB but we seem to have lost ours. If you buy one definitely get that attachment and don't lose it like we did.
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Eng-tips forums: The best place on the web for engineering discussions.
CWNW
if you want frequency response...gain and phase then you need a gain/phase analyser....and i believe only two companies in the world do these..
one is ridleyengineering
other is .....i forget but i think its like an irish name.
Also, what about getting a cheap deal with a differential probe and scope together...the diff probe is likely to be more expensive than the scope.
remember if the voltage you are measuring has edges of more than 50 to 60V per microsecond then you will need an isolated differential probe...as has previously been discussed on this forum....
if you want frequency response...gain and phase then you need a gain/phase analyser....and i believe only two companies in the world do these..
one is ridleyengineering
other is .....i forget but i think its like an irish name.
Also, what about getting a cheap deal with a differential probe and scope together...the diff probe is likely to be more expensive than the scope.
remember if the voltage you are measuring has edges of more than 50 to 60V per microsecond then you will need an isolated differential probe...as has previously been discussed on this forum....
treez,
If I remember correctly the HP 4194A is the network analyser I used in the past for gain-phase response tests.
Most of the S-parameter test sets can do gain-phase too but they're really RF tools and their LF response response usually cuts off around 100kHz or so. It's ages since I saw one of them and the more modern ones might have better LF response; the one I used was also HP and occupied about 8U of rack space. Today it is probably hand held.![[smile]](/data/assets/smilies/smile.gif "[smile] [smile]")
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If we learn from our mistakes I'm getting a great education!
If I remember correctly the HP 4194A is the network analyser I used in the past for gain-phase response tests.
Most of the S-parameter test sets can do gain-phase too but they're really RF tools and their LF response response usually cuts off around 100kHz or so. It's ages since I saw one of them and the more modern ones might have better LF response; the one I used was also HP and occupied about 8U of rack space. Today it is probably hand held.
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If we learn from our mistakes I'm getting a great education!
Yes you are right ScottyUK,
For some reason i was thinking that the OP was going to be doing SMPS's....which need the Bandwidth to go down to near 0Hz like this one
whereas HP4194A only goes down to 10Hz
....10Hz not being useful for todays SMPS where a PFC stage is common and has bandwidth often as low as 5Hz in the voltage loop.....but then again, that was me assuming that OP was doing frequency rresponse of SMPS's , which he may well not be
For some reason i was thinking that the OP was going to be doing SMPS's....which need the Bandwidth to go down to near 0Hz like this one
whereas HP4194A only goes down to 10Hz
....10Hz not being useful for todays SMPS where a PFC stage is common and has bandwidth often as low as 5Hz in the voltage loop.....but then again, that was me assuming that OP was doing frequency rresponse of SMPS's , which he may well not be
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