<p>S1 spends half his waking life building electronic circuits. I’d like to give him a digital oscilloscope for Christmas. I’m having a hard time figuring out what capabilities he needs (a high-bandwidth model can cost as much as $20,000 new!). I’d heard that Ebay is a good source of used electronic equipment, but everything I’ve seen there that is used is sold “as is.” Any suggestions for brands, models, or capabilities, or for good sources of reliable used equipment?</p>
<p>Any tech school near you? Some of them have swap meets and boards where info like this is exchanged. </p>
<p>You could also try craigslist because then you could actually see what it looks like. </p>
<p>I wouldn’t be afraid of buying something on ebay “as is” if I trusted the seller - from rankings. I wouldn’t buy one that was being sold one off, but some sellers are guys who really love electronics and buy stuff like this really cheap, fix it up and sell it. A friend’s dad did this with old radios and the like and he did great work.</p>
<p>[DIY</a> Pocket-Sized Oscilloscope Kit For $33 - Digital storage oscilloscope - Gizmodo](<a href=“DIY Pocket-Sized Oscilloscope Kit For $33”>DIY Pocket-Sized Oscilloscope Kit For $33)</p>
<p><a href=“http://www.mcmelectronics.com/search.aspx?C=3831758&K=scope[/url]”>http://www.mcmelectronics.com/search.aspx?C=3831758&K=scope</a></p>
<p>The first is a kit that looks nice for a starter DIY scope. The 2nd is the scopes offered at MCM. I’d be comfy buying a low end scope - they don’t have to be megabucks to start out with.</p>
<p>My son bought his on EBay.</p>
<p>What exactly did he buy, dmd77? Do you know the brand and model, or the bandwidth?</p>
<p>Treetopleaf, we’re looking for something that costs up to $400. S1 is very serious about this, and we want to get him something that will serve him well for a long time.</p>
<p>I will look into tech schools, Lergnom. Craigslist will be too hit-or-miss, given that I want to find something in time for Christmas.</p>
<p>NYMom - I don’t know if it would be practical for you, but did you check Craigslist for the SF Bay Area? I just did, and I see an ad posted by someone with a Stanford address for a “pulse and function generator”. He says he also has an extra digital oscilloscope, and he says he’ll take the gear back for up to half a year. You would have to deal with shipping unless you have a friend in this area who could handle it for you. This ad has a phone number in it - PM me if you can’t find it.</p>
<p>Another approach is to try to find a current HP employee (maybe in Waltham, Mass?) who could find you something through an employee bulletin board.</p>
<p>[OMNI</a> Controls Online Catalog :: 800.783.6664](<a href=“Test, Measurement & Electrical Test Equipment- Omni Controls”>Test, Measurement & Electrical Test Equipment- Omni Controls)
This one sells for $469.</p>
<p>What is his digital clock speed?
An osc should be at least as fast as his clock for digital uses.
If analog use, is he in the RF realm or lesser?</p>
<p>Tektronix, HP, and B&K are popular brands. Probes are very important and are a significant cost of the package.</p>
<p>My son bought a used analog Tektronix oscilloscope for very little money ($25?). It was the same model that my husband used in the mid-80s when he was starting his first company (when it cost thousands of dollars), so the two of them spent a little time repairing it and getting it working well again. </p>
<p>I’m not sure you want to surprise your son with an oscilloscope… he may have very specific wants/needs.</p>
<p>(If your son is good with circuits and diagnostics, he may enjoy getting an “as is” oscilloscope working properly.)</p>
<p>LongPrime, How do I find his digital clock speed? And what clock do you mean? He is building circuits on breadboards at the moment. I have no idea what frequency he is working in. Thank you for the brand recommendations, and for letting me know about the probes.</p>
<p>dmd, My son would probably love a broken piece of junk - he collects them, and cannibalizes them for parts!</p>
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<p>Then I wouldn’t get a used one. You can find new ones in that price range with maybe only a little sacrifice of function.</p>
<p>The problem with used ones is that the newer style digital scopes, with LCD screens, are for the most part not user-serviceable. If it’s broke it’s broke, and only parts from the manufacturer will fix it.</p>
<p>Also, if he is only working with purely digital circuits, then an oscilloscope is the wrong tool. Scopes have only a few channels, whereas a digital logic analyzer will have dozens to hundreds of channels for the same price.</p>
<p>As for frequency/bandwidth: without knowing more, a 50/100MHz scope would likely cover almost all hobby or household applications. (For NYMom’s checkbook’s sake I hope he is not doing RF! 
)</p>
<p>One thing to consider - USB scopes are very popular among hobbyists. They are usually less pricey for the same features because they interface to your desktop/laptop instead of having their own screen. Plus, it is easy to record/save data to your computer. I’ve heard good things about Parallax ([Parallax</a> Home](<a href=“http://www.parallax.com/]Parallax”>http://www.parallax.com/), <a href=“http://www.parallax.com/Store/Accessories/Tools/tabid/162/List/0/ProductID/46/Default.aspx?SortField=ProductName%2CProductName[/url]”>http://www.parallax.com/Store/Accessories/Tools/tabid/162/List/0/ProductID/46/Default.aspx?SortField=ProductName%2CProductName</a>)</p>
<p>Thank you so much, jbusc! The USB scope is a great idea - I will look into those. My son is working with analog circuits - oscillators, speakers, etc.</p>
<p>not what I originally was looking for. I wanted to add this information, in case anyone else is in the same situation.</p>
<p>I’ve been researching this and, based on suggestions from a professor who teaches undergraduate electronic labs, and the people at the site below, I decided to start with an analog scope:</p>
<p>[BK</a> Precision 2120B, 30 MHz Dual-Trace Oscilloscope, B+K Precision 2120-B - at Test Equipment Depot](<a href=“http://www.testequipmentdepot.com/bk-precision/oscilloscopes/2120b.htm?gclid=CKfSxoz23p4CFWZ75Qodh1LHKw]BK”>http://www.testequipmentdepot.com/bk-precision/oscilloscopes/2120b.htm?gclid=CKfSxoz23p4CFWZ75Qodh1LHKw)</p>
<p>The professor made the point that most people who are serious about electronics end up with several scopes eventually, and that it was hard to make a mistake buying the first one. He like the idea of starting out with an analog model. The people at testequipmentdepot.com made the same suggestion, saying that it was a good idea for students to learn to use an analog model before moving on to digital equipment, because they would really understand what they were doing. He compared it to learning to do math on paper before using a computer. They are having a big sale on this model, so I got it for $350 including shipping.</p>
<p>Thanks to all who posted suggestions. I am sure that I will refer to this thread again for future birthdays and Christmases.</p>
<p>NYMom: that sounds like it will be a hit. Let us know.</p>
<p>Hi, I’m not a regular on CC, but have occasionally dropped by. This thread caught my eye because I’ve been searching for an affordable entry-level oscilloscope for a young man with a keen interest in electronics. </p>
<p>The 2010 price on the scope that NYMom purchased last Christmas is $379. I’d be interested to know how her son likes his scope after a year of use.</p>
<p>Have any of you CC regulars encountered a better sub-$400 standalone oscilloscope?</p>
<p>I’d also like to hear any contrary opinions on the advisability of starting with an analog scope. In particular, will an analog scope be essentially useless for measurements on a digital circuit?</p>
<p>I’d value your thoughts.</p>
<p>I’ve used analog scopes on digital circuits (including many IBM mainframes, microprocessor circuits, etc.) for years. One doesn’t need a digital scope for digital circuits. The ‘digital’ in the digital scope is mostly in the way it works internally - not the types of circuits it can be used with. The important point as to the limitation of the scope for digital circuits is how ‘fast’ the scope is - i.e. whether it can handle the nanosecond range okay.</p>
<p>I’ve mostly used Tektronix, HP, and Philips scopes. These scopes can get very expensive but used ones might not be so costly and they should be fine as long as it’s in decent calibration, everything works, and it handles what you need.</p>
<p>For a first scope for a hobbyist it’d be great if you could get a good scope from a top manufacturer (like one of the above) as a used scope. There may be some decent digital scopes that connect to a laptop as the display but I haven’t played with any of those.</p>
<p>ucsd<em>ucla</em>dad, thanks for your thoughts. Your post goes straight to the heart of the question. </p>
<p>Scopes that are under $1000 are typically in the 20-50MHz bandwidth range. I’ve found used scopes in this price range up to about 150 MHz.</p>
<p>But if digital circuits require a scope in the ns range (which I’m assuming means 1GHz) then maybe our conclusion must be that an entry-level college engineering student scope is simply NOT going to be able to handle digital circuits for under $1k.</p>
<p>An earlier post in this thread suggested that a student would really want a logic analyzer (instead of an oscilloscope) for digital circuits. Would anyone second that opinion?</p>
<p>Sorry, by ns I didn’t necessarily mean a 1 GHz scope. The 200MHz HP scope I have gets down to around 10ns/div and is generally fine for digital circuits in addition to analog. At 10ns/div one can usually see malformed digital signals, calculate circuit delays, see overshoot/undershoot, calculate the difference in timing between signals, etc. This brings up another point - there are ‘single channel’ scopes and multiple channel ones. Having 2 channels is very handy and in many cases necessary in order to compare 2 signals with each other to see timings and what one’s doing relative to another. </p>
<p>A logic analyzer can come in handy for digital circuits but the ones I’ve used were pretty expensive. It depends on what one is doing as to whether one needs a logic analyzer or not. An o-scope is more useful generally and is used for all kinds of circuits - both analog and digital. A logic analyzer is handy when one wants to, for example, see what’s going on on a data bus and to store state changes to see what the data/address lines, for example, are doing. </p>
<p>If computer professionals can use a good scope (ex: the 200Mhz one I have or better, sometimes even a bit slower) to troubleshoot the majority of issues including with bringing up newly designed/prototypes circuits, then it seems that it’d be a good start for a student and a far cry better than my first scope - a slow, single channel, Heathkit I built (I think).</p>
<p>It really depends on the circuit types (straight combinational digital logic, microprocessors, address/data buses, chip type (TTL, CMOS, ECL, etc.), analog, etc., and how one’s using it (single channel, dual channel, external trigger, etc.) as to what’s needed.</p>
<p>I really don’t know what’s available currently since I haven’t needed to buy a scope in quite a while. Some of the new less expensive ones that use a PC as an output device might be pretty good for the price but I haven’t used them.</p>
<p>Again you need to know the device-under test, digital clock speed.
For hobbiests, probably a lower, mid priced unit is good enough.
Depending on your OSC, you need to match your probes to your test unit. </p>
<p>Many applications, an experimenter only needs to know if the signal is present and if analog, at what levels.
Most problems are assembly related- Get a very good solder iron, a head band magnifier, a power supply, and adequate light.</p>
<p>ucsd<em>ucla</em>dad, thanks for another truly helpful post. I see a used Tektronix TDS420, 150MHz, 100 MSa/s, 4-channel scope on CraigsList for $550. Looks like a great buy; maybe I’ll go look. Thanks for taking the time to educate me.</p>