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oscilloscope Answered

I'm thinking about getting an oscilloscope (on ebay) because I've always wanted one (and I'll probably need them on upcoming projects. Plus I just got some birtthday money (yay, I'm 14 now!). anyways, I need help of what is considered a good oscilloscope. I don't want to buy one and then later find out it's a piece of crap.

37 Replies

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alex3194ohio (author)2008-03-18

Hey, I'm 14 too! And I'm also looking For an oscilloscope. Funny! =)

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guyfrom7up (author)alex3194ohio2008-03-18

here's mine, 100mhz, costed be about 150 total.

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tech-king (author)guyfrom7up2008-03-18

im not jealous of your nice oscilloscope. honest. (oscar: blatant engineer lie)

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guyfrom7up (author)tech-king2008-03-18

you keep on saying oscar in your posts, is it your name?

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Goodhart (author)guyfrom7up2008-03-18

IIRC he mentioned that he named his lab coat: "Oscar" (the cost of being lonely LOL).

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tech-king (author)Goodhart2008-03-21

im not that lonly. there is a girl i like. i do send roses on valentimes day to her. i did get her timbits. i called it oscar because i was lonly, under the influence of the book have space suit will travel (robert heinline) and because i was impressed with how well thought out the lab coats were.

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Goodhart (author)tech-king2008-03-21

:-) Sorry, I was just messin with you :-) My first car was named Obadiah, so I know how it goes ;-)

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Goodhart (author)Goodhart2008-03-21

BTW: I love what we call "doughnut holes" down here in the states (what you call Timbits) :-)

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tech-king (author)Goodhart2008-03-21

now my gift of timbits feels cheap. thanks a lot!

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Goodhart (author)tech-king2008-03-21

Why ? They rank almost as high as Chocolates (especially if they ARE chocolate flavored) around here :-) Hey, completely off subject, but something this reminded me of (yeah, I know, I have a very WEIRD sense of subject connection), the other day I saw some Canadian Geese headed north.....and then wave after wave of them came flying up. I had never seen so many blanket the skies all at once like that. I was simply amazed. I stood there for nearly 5 minutes watching them all. Anyway, I just wanted to share that (whether you care or not LOL)

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tech-king (author)Goodhart2008-03-21

i care for a somwhat sadistic reason: in summer, they cover the beaches near lakes with dung. hence the expression smoothe and fast like poop through a goose. seeing as they are flying over you .....

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Goodhart (author)tech-king2008-03-21

Honestly, I was very surprised that I did not feel any "white n green rain" with as many as there were. I have NEVER seen such a sight as that though before. It was awe inspiring. My wife, who was inside the restaurant's at the time, missed the majestic event.

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tech-king (author)2008-02-25

a good one works and is precise. it can also be tuned if needed. thats a good start.

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guyfrom7up (author)tech-king2008-02-25

how many mhz do you recommend?

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NachoMahma (author)guyfrom7up2008-02-25

. Depends on what you're going to measure. Rule of thumb is twice the freq of what you are measuring.

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trebuchet03 (author)NachoMahma2008-02-25

It's actually more than a rule of thumb... I just can't remember the guy's name that the rule is named after...

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uguy (author)trebuchet032008-02-26

I believe it was Sir Edmund Thumb

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beado4ever (author)uguy2008-03-21

Was he related to Baron Right-Hand Rule ESQ?

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Goodhart (author)beado4ever2008-03-21

And related to the Frenchman Noah Soree` Thumb

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trebuchet03 (author)NachoMahma2008-02-25

Okay, I had to break out my notes to find it.... I remember learning it, but obviously didn't retain enough to remember it's title :p It's called Nyquist Theorem - accurate measurements (without or with less aliasing) need to have a sampling frequency of at least 2x the frequency being measured. Keep in mind, this was originally developed during a time when digital tools and acquisition didn't exist and sampling rates were much lower than today...

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guyfrom7up (author)2008-02-25

problem solved, I found this free program called LPTScope that transforms you computer into an osciloscope (up to 15 ghz! Or by your fance law thing, 7.5ghz!). All it costs is a couple dollars to make the circuit to attach to the printer port of your computer. I feel like such a programmer, usb to boarduino, serial to pic programmer, now parallel to oscilloscope. :)

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guyfrom7up (author)guyfrom7up2008-02-25

eh, never mind, it can only record up to 5 volts, which I think is a bit low...

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NachoMahma (author)guyfrom7up2008-02-27

. Voltage divider and/or attenuating probe. Viola!

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guyfrom7up (author)NachoMahma2008-02-27

eh, voltage deviders are good and all, but would not be too practical to use. It'd be like making your own multimeter, you have to adjust the devider, see the outcome voltage, and calculate it... everytime.

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Goodhart (author)guyfrom7up2008-03-18

Hmmm, I need to find my plans for constructing different frequency probes now ;-)

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guyfrom7up (author)2008-03-02

i bought one!!!! It's 100mhz Today I am truely an electronic guru, and I have an oscilloscope to prove it! "Do you know the answer to this really complex electronic question?" "No, but I have an oscilloscope!" "ooooooo"

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guyfrom7up (author)2008-02-26

well, I'm bidding on some on ebay (it's hard to find a good one that's not too expensive, and doesn't say something like it may not work), so i might havbe a new (for me, really probably old) oscilloscope! I'll post pics if I get one. mine won't be as small as westfw's, but space is not really a problem for me.

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guyfrom7up (author)guyfrom7up2008-02-28

eh, I lost... It seems like a lot more people want olscilloscopes now than 1 week ago! any suggestions?

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uguy (author)2008-02-26

You might want to check-out a PC scope by Parallax, the Basic Stamp people.
http://www.parallax.com/Store/Accessories/Tools/tabid/162/CategoryID/37/List/0/Level/a/ProductID/46/Default.aspx?SortField=ProductName%2cProductName

Works great with a laptop for remote/portable use or with a desktop at home/workshop.

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guyfrom7up (author)uguy2008-02-26

eh, I think it's a bit pricy (I don't have a huge budget), plus it's only 200khz, which is only 0.2 mhz, and cheap oscilloscopes (as little as 20 bucks or less!) are about 10mhz

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westfw (author)guyfrom7up2008-02-26

Ah; you didn't mention your actual budget. It's REAL hard to beat the price of some of those used "mainframe" scopes. Watch out for shipping costs, though.

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westfw (author)2008-02-25

I splurged once on a (new) TDS210 60MHz digital scope. The killer feature is that it's only about six inches deep (LCD display) and lightweight, so it fits up on top of my desk hutch instead of needing dedicated space (and it could be "put away" (hah!) in a cabinet or on a bookshelf, if necessary.) I don't use it as much as I thought I would; I probably should have gotten one of the PC-based scopes. I also wish it had a way to upload traces to a PC (it does, but only via an expensive and largely obsolete add-in card.)

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guyfrom7up (author)westfw2008-02-25

pc-based osillpscope (if that was a spelling bee question, I'd fail)? What's that? Is it cheaper? Cause that might be perfect! I have one of those desks where it has a wide middle drawer, 3 drawers on the right (the bottom one can be used for files), and I'm transforming my right side of the desk (my pc takes up the left) into a prototyping station. Since my b-day I now have: the giant jameco breadboard (kciks the tiny old radioshack one I had before!) make bomb defuser (it is soooo nice, I can strip wires in like 0 seconds flat) my pic programmer (actually, if anybody's good at pic I need help setting it up, I'm using IC-prog and I'm having "Osilator Calibration values" problems, then after that I have the generic 0000h problem thing. I'm trying to program a 12f675 on my PIC-PG2, the one from sparkfun. after that off topic thing (it'd be really nice to get that programmer fixed) what's a pc-scope?

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westfw (author)guyfrom7up2008-02-25

Well, if you're willing to top out at audio frequencies and forgo some accuracy in amplitude measurements, there is software and very cheap hardware that will turn some of your sound card inputs into scope channels, and your parallel port into a logic analyzer. (I talk about this some here)
Then there are a bunch of varying price/capability devices that are essentially analog sampling front ends that send the captured data to a PC (ie over USB) for display and analysis. These range from DIY to not-too-expensive PoScope at about $100) to much more expensive [http://www.saelig.com/miva/merchant.mvc?Screen=PROD&Product_Code=PS035&Category_Code= $2000+ for this PICO unit (but presumably cheaper than a full scope offering similar speed and features.)
Look through any issue of a magazine like Circuit Cellar Ink and you'll find lots of ads...

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Goodhart (author)2008-02-25

Here is a link to a PDF for an oscilloscope Primer The introduction is there, and then off to the left is the link for the PDF. It is nearly 1.5 Meg so if you are on dialup, it will take a few minutes.

Here is an example of Tektronix's rated best one...for comparison.

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Goodhart (author)Goodhart2008-02-25

PS: I have 2 Analog Oscilloscopes at home, but haven't had the money to invest in a digital one. I don't really use it that often anyways.

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