Second thoughts on buying my lab set up. - Page 1
Forum section: electronics / general

author: Mattjd
author_rank: Regular Contributor
timestamp: February 04, 2017, 09:04:11 pm
content: So in 2016 before the fall semester started, I was working full time (I was in transition from community college to university). Due to how much I made (35k) and how much I paid for school. I got a big fat tax return, add to that what my sister owes me, and I am sitting on $4800.I had plans of buying electronics equipment because I am an ECE student, am highly interested in electronics, and because I believe the hands on experience with be invaluable. Everything priced out, would be about $2500 or so. Maybe a bit more. I haven't used any discounts.I was gonna buy afunction gendig scopetable top mmhandheld mmpsupossibly a used analog scope (bc they're cheap and to calibrate my own stuff)work bench with esd tophot airreworkelectronics viseMAYBE a LCR (most likely not)ICs and passive I'm not worried about, can get them at school...already got a soldering ironI'm just starting to get cold feet bc its so much money, and I feel irresponsible spending it. I had all plans to work through uni as I only have to take a max of 12 credits a semester. Unfortunately I had to quit my job due to scheduling conflicts, and as a result, had to take out extra loans for living expenses.Now I am not short on money at all....I don't know if irresponsible is correct word, but more like wasteful. I can always use the stuff at school, of course the availability is no where near the same.I'd like peoples opinions.

author: gnavigator1007
author_rank: Unknown
timestamp: February 04, 2017, 09:24:38 pm
content: I would recommend waiting to buy most things until you actually need them. I'd get a scope and a couple multimeters first. Maybe a cheap function gen too. But having money owed to you is not the same as having that money now. Being unable to work at the moment you should definitely be prepared for other unexpected expenses. The hands on experience is valuable with these things, but it will take some time. You'll get there

author: eugenenine
author_rank: Frequent Contributor
timestamp: February 04, 2017, 09:42:35 pm
content: I tend to buy something inexpensive /used to learn on. Then you can learn what features you need/want and buy a better one later.

author: SingedFingers
author_rank: Frequent Contributor
timestamp: February 04, 2017, 10:02:20 pm
content: Quote from: gnavigator1007 on February 04, 2017, 09:24:38 pmValuable advice. Definitely agree.You can get a long way with a fire stick, a shitty DMM, a power supply or some batteries and some parts. Only in the last 5 years I have crawled out of 15 years of debt and into the land of disposable income and I still wouldn't splash on kit and buy spares/repair kit exclusively where I canThe only new things I bought are a Weller WTCP51 and a Rigol DS1054Z with an unexpected tax rebate. The latter I regret buying and am selling it to a colleage on payday as I don't need it and am good with the £10 philips scope I have. The Weller was worth the money though.Incidentally I did an EE degree and skip dived or built my kit and used the university labs. You don't need a lot of stuff for a personal lab at that stage.

author: tautech
author_rank: Super Contributor
timestamp: February 04, 2017, 10:03:44 pm
content: Quote from: gnavigator1007 on February 04, 2017, 09:24:38 pmMostly this. ^^^But with all you have listed it should be possible to get a package deal and get somereasonableequipment that could serve you well for years.If you plan to do any repairs, maybe to earn a little more, you'll need a LCR meter of some sort.

author: Mattjd
author_rank: Regular Contributor
timestamp: February 04, 2017, 11:39:38 pm
content: Quote from: gnavigator1007 on February 04, 2017, 09:24:38 pmI should say, I have the cash from my sister already. What I meant is that between my tax return and what she payed me back I haveamount of money. The unexpected expenses is sitting in the back of mind too.

author: Mattjd
author_rank: Regular Contributor
timestamp: February 04, 2017, 11:40:43 pm
content: Quote from: eugenenine on February 04, 2017, 09:42:35 pmthis is a good point. All the more reason to use the university equipment first. Its also why I didnt add some of the more exotic equipment to my list like an LCR,Logic Ana, or RF spec Ana. The later 2 of which are major $$.

author: Mattjd
author_rank: Regular Contributor
timestamp: February 04, 2017, 11:43:09 pm
content: Quote from: tautech on February 04, 2017, 10:03:44 pmRepairs was something I thought about as a way to recoup money but it seems that electronics repairs is pretty much dead with all the smd, built-to-break, and cheap cost of new items/high cost of replacement parts.

author: rstofer
author_rank: Super Contributor
timestamp: February 05, 2017, 12:06:22 am
content: Anecdotally, it is possible to get through EE school without ever seeing an oscilloscope. Or something close to that... You certainly don't need to own one!OTOH, you are the perfect candidate for the Digilent Analog Discovery because it has everything you will need to get through EE school and it's only $279. A dual channel scope, dual channel arbitrary waveform generator, 16 bits of digital IO that can be used as a Logic Analyzer (includes decoding), dual adjustable +- 5V power supplies and so on.http://store.digilentinc.com/analog-discovery-2-100msps-usb-oscilloscope-logic-analyzer-and-variable-power-supply/I have one of these and if I didn't have the rest of my stuff, it wouldn't matter. Are there better scopes? Sure! Better signal generators? Sure! More capable power supplies? Yep! But you can't get them all in a small box for $279.This device was designed specifically for EE students. I would recommend starting with the Analog Discovery and see how far it takes you. When you outrun its capability, buy something better. In the meantime, you will continue to use other parts of the AD.

author: tautech
author_rank: Super Contributor
timestamp: February 05, 2017, 12:36:08 am
content: Quote from: Mattjd on February 04, 2017, 11:43:09 pmNot exactly the right attitude for a budding EE.SMD will be your world, learn about it and get to love it.

author: Mattjd
author_rank: Regular Contributor
timestamp: February 05, 2017, 12:39:05 am
content: Quote from: tautech on February 05, 2017, 12:36:08 amI dont want to say I am against smd. Its just a reason that repairs seems to be going away. At least this is what google searches tell me. The biggest way that new electronics are so cheap and replacement parts can be nonexistent to damn near the cost of the a new piece, and sometimes due to the SMD its best off just replacing the whole board, again jacking up the cost of the repair.

author: Ian.M
author_rank: Super Contributor
timestamp: February 05, 2017, 12:40:25 am
content: Quote from: rstofer on February 05, 2017, 12:06:22 am+1, and unless you are going to uni in your home town, you would have to contend with finding space for your lab in student accommodation or moving it from one shared apartment to the next. Maybe consider what the best lab you can fit in a briefcase (or other reasonable sized flight case) could be - assuming you can find a card table to set up on.e.g: an Analog Discovery, pocket DMM, and a minimum of a CAT III handheld DMM, temperature controlled soldering iron, heat resistant mat, helping hands, largest roll of anti-static mat you can reasonably fit in the case, tool bag or roll, illuminated bench magnifier, 0-30V 1A PSU for when the +/-5V from the Discovery isn't enough - possibly as a dual tracking +/- 0-15V PSU, Solderless breadboard), space for a couple of MCU development kits, an organiser box for current parts and enough space remaining for a reasonably sized PCB you are working on, and don't forget power distribution, so you can get it all plugged in assuming you've only got a single wall socket available.I'd leave all the dedicated SMD tools and standalone bench testgear out for now - you've got access at the moment, and you'll only have to move it all cross-country when you graduate. However, if you get a chance at good gear for cents on the dollar (e.g. if the uni is selling or scrapping older kit), grab it - but have a plan in place for where its going to be stored long term and how you are going to ship it there.

author: tautech
author_rank: Super Contributor
timestamp: February 05, 2017, 12:49:42 am
content: Quote from: Mattjd on February 05, 2017, 12:39:05 amAnd as experience grows and an intuition is gained for common fault modes in failed products and along with some confidence to substitute hard to obtain parts with more available replacements you'll think differently in a few years.Datasheets and Google are your friends.Enjoy the journey, there is much to learn.

author: Mattjd
author_rank: Regular Contributor
timestamp: February 05, 2017, 12:54:09 am
content: Quote from: Ian.M on February 05, 2017, 12:40:25 amI do in fact commute. It is only 15 minutes from my home. More like 30 because traffic in town is always bad, but realistically only 15 minute commute.

author: SkyMaster
author_rank: Frequent Contributor
timestamp: February 05, 2017, 05:27:21 pm
content: Quote from: Mattjd on February 05, 2017, 12:39:05 amThe cost of repair being unfavorable when compared to buying a new replacement item has nothing to do with SMD. The repair would be done locally at (relatively) high cost, while the new device is manufactured in a third world country (with extremely low wage, almost non existent environmental laws, etc). In these third world countries, they repair everything because they cannot afford to buy a new replacement item; which is for them a high cost item.When you repair something for yourself, your time cost you nothing. But in order to perform a repair, knowledge is required.

author: nctnico
author_rank: Super Contributor
timestamp: February 05, 2017, 05:56:15 pm
content: Quote from: Mattjd on February 04, 2017, 11:43:09 pmIf you want to make money with repairs then fix PC and tablet problems.If you live 30 minutes from school then IMHO it is wise to wait until you have a better idea of what you'd like for your own lab. Also look at buying second hand to save money. Currently there are many nice used GW Instek power supplies and bench DMMs on Ebay.

author: Mattjd
author_rank: Regular Contributor
timestamp: February 05, 2017, 06:32:23 pm
content: What do you guys mean by "wait until I know exactly what I need"? I feel like the stuff I listed is like the basics of any electronics lab. Or are you referring the precision and/or amount of "stuff" that can be put out by each device. Like the amount of amps/voltage for a psu, if I need it to be variable, etc.

author: nctnico
author_rank: Super Contributor
timestamp: February 05, 2017, 06:45:18 pm
content: Quote from: Mattjd on February 05, 2017, 06:32:23 pmYes. Things like number of PSU output channels, analog versus digital oscilloscope, 3.5digit DMM versus 4.5 digit DMM, etc. It also depends on the kind of projects you want to make. Just ask yourself what you like about the instruments in school and what you don't like.

author: Ian.M
author_rank: Super Contributor
timestamp: February 05, 2017, 07:29:40 pm
content: I'd initially put up to $800 into good easily portable equipment and leave the other $4000 as a cushion in the bank. You cant eat test equipment, nor can you easily swap it for car repairs etc. Its different if you have a permanent job bringing in money each month, but as a student, only buy bench equipment you actually *NEED*

author: Berni
author_rank: Super Contributor
timestamp: February 05, 2017, 07:34:27 pm
content: Its not all about equipment. While yes it is nice to have lots of test equipment to get any task done quickly and efficiently, but its not essential. Using just the basic tools you can get pretty far, just that your measurements might not be as good or you might spend 3 times longer finding the simple fault.You want to start small and gradually buy more and better equipment as you see what you need. You don't need to get great top quality stuff off the start. Here is what i consider essential:-Multimeter (No need for a fancy $300 meter, get a few cheap $50 ones, two different ones is a good start, buy better ones later as more multimeters can come handy)-Soldering iron (Must be a temperature controlled soldering station but no need for it to be really fancy but getting a known brand is a plus)-Hot air station (Very useful these days with SMD stuff and you can get it really cheap from china, the cheap ones actually work great)-PSU (Good to get two, anything above 15V 2A is usually fine, if you have the money i really like my Rigol DP832 since its 3 supplies in one and very accurate)-Misc tools (Twezers, cutters, screwdrivers, solder wick, flux ,good large solder sucker(the small ones are all crap), magnifiers, crocodile leads etc )-Parts ( Common resistors and capacitors, wire, breadboards, perfboards, LEDs, jelly bean chips)With this gear you can build all the common DIY projects, repair a lot of things and in general get a understanding of electronics.The next purchase after this should be an oscilloscope. It is the 2nd most important piece of test gear in electronics(1st being a multimeter) as it allows you to look in to exactly what your circuits are doing in detail. This opens the door to advanced component level repair of equipment and lets you troubleshoot your own circuits a lot faster when they don't work. While getting an old analog scope is a good learning experience the thing is that you can get a digital scope pretty cheap now and it allows you to see things that you can't with an analog one. Its worth looking for older used scopes, but something like a new Rigol or similar scope is still a great choice. To start with 4 channels and 50MHz is all you need.At this point you now have a mature electronics lab that can do all the common things. You might want to get things like a better bench multimeter that you can really trust what it shows or a basic signal generator to more easily provide stimulus to your circuits. But on from there the next equipment purchases are entirely dependent on what sort of work you end up doing. For example if you get in to radio stuff a lot it might be good to buy a spectrum analyzer and a RF signal generator. Maybe you are doing precision stuff and need a good 6 digit multimeter, perhaps you got in to high speed digital and now need a better 1GHz scope and maybe a logic analyzer too, maybe you work on things that need more specialized power supplies like 300V or maybe something that needs 20A to run. Or maybe you design a lot of power supplies yourself and need a DC electronic load to test them.Also don't spend all your money on test gear. You will want to have money leftover for buying parts to build your projects out of. You can also save a lot of money on the more expensive equipment by buying it used on places like ebay. Once you are good at electronics you can try getting even better deals by buying cheap broken equipment and fixing it yourself (Tho that caries a risk of not being able to fix it)So in short you don't need a fully equipped lab just to start. Test gear is expensive so its much easier to absorb the cost over the span of a year or two and once you are experienced its easier to decide what gear is best for your use case. If you wan't to jump in feet first you can get a cheap scope off the bat but don't worry about any other equipment as you will know when you need it.

author: mtdoc
author_rank: Super Contributor
timestamp: February 05, 2017, 07:43:06 pm
content: Quote from: Ian.M on February 05, 2017, 07:29:40 pmYes. This. For $800 you can equip a very functional student lab:A couple of $100 range DMMs.$100 for a Hakko 888$100 for a decent power supply.$300 for a Analog Discovery with BNC adapter - gets you a 30MHz (not 10MHz as marketed) scope, logic analyzer and function generator, plus decent low frequency spectrum and network analyzer.That leaves another $100 or so for hand tools and supplies.

author: chicken
author_rank: Frequent Contributor
timestamp: February 05, 2017, 07:46:54 pm
content: If you have to take out loans for living expenses you are short on money, no matter what your current bank statement says.As others suggested above, spend a few hundred on what you need for your projects at hand, and defer the rest for when you can't do without any longer. Being that close to university may also allow to use their gear for occasional higher end requirements.

author: Mattjd
author_rank: Regular Contributor
timestamp: February 05, 2017, 08:09:07 pm
content: Quote from: mtdoc on February 05, 2017, 07:43:06 pmthe Hakko 888 is the exact soldering iron I have.

author: Mattjd
author_rank: Regular Contributor
timestamp: February 05, 2017, 08:40:50 pm
content: I think I'm gonna go with the ~800 limit. Maybe raise it to $1100 (not counting tax), but keep it at that. The reason I say $1100 is because that is the amount my sister owed me and payed me back. Meaning I wont have to touch my tax return other than for taxes on these items. I'll have enough for learning the basics, and the heavy hitters will always be at school.I have the Hakko 888 already, and I have a multimeter also. Its a Fluke 117 (of course this doesnt measure micro volts or amps only mili-volts). I have an asortment of hand tools too. Everything I would need, expect maybe a pull through bender. Development board wise a basic breadboard and FPGA (Altera DE0). I'd like to get a MCU kit or 2.So, I would needPSUAnalog Discovery2nd DMMI was originally looking at the Signstek UNI-T UT139 because I've heard good things about it and its pretty cheap right now on amazonhttps://www.amazon.com/dp/B00XOSD79G/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=17FEZVTW6AC2H&coliid=I3JWC8EH92585BSo, that's $340 out of my $1100 budget, dropping me to $760.If some of you are suggesting two PSU should I just blow my load and get the Rigol DP832 I was originally gonna buy?

author: raspberrypi
author_rank: Frequent Contributor
timestamp: February 05, 2017, 08:55:40 pm
content: You should buy the new agilent 300 GHz scope. Its only $999,999.00, and get a hayco. Don't think of it as spending money think of it as investing in your future.

author: rstofer
author_rank: Super Contributor
timestamp: February 05, 2017, 09:05:07 pm
content: Quote from: Mattjd on February 05, 2017, 06:32:23 pmI have always had a scope and, by always, I mean clear back to when I built one from the ARRL Handbook in the late '50s when I was maybe 12. I have always had a V-O-M (multimeter) and, at one time, a VTVM (Vacuum Tube Volt Meter). That's it!For power supplies I would use batteries or wall warts. Signal generation wasn't a consideration since I played in the digital domain. So, I didn't have a power supply or a signal generator until this year (when I'm 71) and, other than the Analog Discovery, all I have is a cheap FG085 for a signal generator. I did buy the Rigol DP832 and it's just great. But I bought it because I could, not because I absolutely had to have it.I also bought the Rigol DS1054Z last year because I could. I wanted to play with a DSO but I still have a Tek 485 that I bought back in 2004 for about $200. I didn't need the DSO, I just wanted to play with one.I have been messing around with this stuff for a few decades and I still don't have a stand alone function generator of any quality and I may never. I get along with what I have and I don't tend to do a lot of analog.So, by wait until you NEED it, I would suggest to not buy anything until you simply can't progress without it. You might be amazed with what you can build without a "complete" lab. Yes, a full lab is great but I still don't have one.As a student, if you really want to get your hands dirty, I would still recommend the Analog Discovery and spend some money on components. I tend to buy parts in assortments unless I am buying for a specific project. I often overbuy project components: I need 5, I order 10, that kind of thing.Something like this:http://www.jameco.com/z/TRANSISTOR-KIT-560-Piece-Transistor-Component-Kit_82595.htmlYou can check the site for resistor, capacitor and transistor assortments. The inductor assortment is pretty thin.You can get much cheaper assortments on eBay. Maybe the quality will be adequate.

author: Berni
author_rank: Super Contributor
timestamp: February 05, 2017, 09:07:39 pm
content: I have that Rigol PSU and its my favorite PSU out of the pile i got. The weird button layout takes a bit of getting used to but once you do it has a great user interface. Its also pretty cheap considering you basically are getting 3 power supplies. The fact that is has 1mA and 1mV resolution on the display also means you don't need a extra multimeter to monitor the accurate value of the current or voltage.It would be smart to use the school as much as possible for the fancier gear, but a scope is a great thing to have once you get in to electronics for real. What scope to get is a whole new can of worms tho as there are so many cheap decent scopes out there now.

author: rstofer
author_rank: Super Contributor
timestamp: February 05, 2017, 09:14:42 pm
content: BTW, the Analog Discovery has dual Voltmeters but they overtake the scope inputs. That may be ok under certain circumstances. They only measure volts DC, AC and TrueRMS.So, if you have a Class A amplifier and you're looking at the input and output signals on the scope, you can just select the Voltmeter tool to get a better estimate of the actual voltages.I don't know if it is handy, I have never the feature.Still, having two or three DMMs is a really good idea. Particularly if you want to wire one in series to measure current and leave it that way.

author: mtdoc
author_rank: Super Contributor
timestamp: February 05, 2017, 10:04:09 pm
content: You're a student, correct? You can get Academic pricing on the Analog Discovery - just check the Digilent website. They used to sell it for an unbelievable price of $100 for students but I think it's higher now - maybe $150??? - I'm not sure. But even at full price it is a good value.Be sure to get theBNC adapter boardfor $20.With that and a set of probes you will get something like 30MHz bandwidth from the scope.For $12 you can get 2100 MHz TP6100 probes on eBay. These probes are surprisingly good. There's a thread on this forum somewhere showing how well they perform when tested.

author: Mattjd
author_rank: Regular Contributor
timestamp: February 05, 2017, 10:07:24 pm
content: Quote from: mtdoc on February 05, 2017, 10:04:09 pmThanks for the tip, I have those exact probes. I bought them on Amazon. At school they dont provide us with probes at all, we're all expected to have our own.

author: Mattjd
author_rank: Regular Contributor
timestamp: February 05, 2017, 10:50:30 pm
content: Does the analog discovery student discount require that the analog discovery be a requirement for the course? I am flipping through the academic verification and it says no such thing but wants a course, professor email, name etc.

author: eugenenine
author_rank: Frequent Contributor
timestamp: February 05, 2017, 11:22:34 pm
content: Most any professor would be happy to vouch for it. They should be happy seeing someone learning on their own.My scope is $40, found it on craigslist. Download one of the apps that will search once a day for keywords and put in tektronix etc.Get through school then you can splurge on expensive gear and pass your used scope on to someone else.Take good notes. I find myself referring back to mine every now and then and wish I had done better.

author: nanofrog
author_rank: Super Contributor
timestamp: February 05, 2017, 11:33:25 pm
content: Quote from: Mattjd on February 05, 2017, 08:40:50 pmFor a PSU, I'd suggest buying used as you can get them for pennies on the dollar. You also get better value on dual or triple output models as they're less expensive than buying 3 separate single output units IME . And they tend to have a better build quality than the low cost supplies available. Best of all, you'll spend less than the DP832.Some examples:HP 6237A Triple Output Power SupplyTektronix CPS250Systron Donner TL8-3 OVLambda LPT 7202-FMPlease note the most expensive is ~$100 shipped.On the DMM front, the UT139C is a great little meter. In fact, I'd recommend you buy 2 for simultaneous measurements. And you can get it for less than Amazonhere.

author: Mattjd
author_rank: Regular Contributor
timestamp: February 08, 2017, 02:15:44 am
content: What's the thoughts onhttp://www.tequipment.net/Extech382203.asp?v=7421it's on sale and with the members discount is probably under $100

author: anfang
author_rank: Regular Contributor
timestamp: February 08, 2017, 02:17:53 am
content: I hope you have permission to "get them from school" - the components, young whipper snapper me lad!

author: nanofrog
author_rank: Super Contributor
timestamp: February 08, 2017, 02:52:38 am
content: Quote from: Mattjd on February 08, 2017, 02:15:44 amThe discount would only bring it to $120.80.As per that Extech PSU, I much prefer proper binding posts.

author: james_s
author_rank: Super Contributor
timestamp: February 08, 2017, 08:51:57 pm
content: I use my LCR meter a lot more than I use my bench DMM. Sometimes a second meter is handy but my handheld Fluke is what I use for most things.

author: mtdoc
author_rank: Super Contributor
timestamp: February 08, 2017, 09:36:04 pm
content: Quote from: nanofrog on February 08, 2017, 02:52:38 amI would not pay $120 for that power supply. In fact, I would not pay $50.As pointed out by nanofrog, there are plenty of quality, used power supplies on eBay.While not quite as high quality as a used HP, Lambda, etc, there are a ton of excellent deals on used GW Instek supplies on eBay from the recent ITT auction. These are surely on par (or better) quality wise with the Extech.For example, you can buyone of thesedual 30V/2A output, tracking +5V fixed (and proper binding posts) supply for $45 shipped.There is not much lost in buying one of these simple linear supplies used versus new. They tend to be very robust and easy to fix if something breaks.

author: Dielectric
author_rank: Regular Contributor
timestamp: February 08, 2017, 10:17:16 pm
content: Quote from: Mattjd on February 08, 2017, 02:15:44 amMy big problem with that is the low current capacity. I've got a similar boat anchor under a table somewhere. I'd want at least 3 Amps, dual supplies haven't been super useful to me.And you have to bring your own probes? What kind of noise is that?Quick story, I had a lab partner who brought his "home kit" in since it was all plugged into the breadboard. I kid you not, it was a Tyco model train transformer and a bunch of wire bread ties. Way less than $800 though...

author: james_s
author_rank: Super Contributor
timestamp: February 09, 2017, 12:39:10 am
content: As with anything, the right power supply depends on what you're interested in doing. If you're doing analog design with op-amps then a dual supply is mandatory, linear is recommended and high current is not really needed. If you're doing digital stuff then those aspects are far less important. Chances are you'll eventually end up with multiple power supplies each particularly suited to different applications.

author: eugenenine
author_rank: Frequent Contributor
timestamp: February 09, 2017, 12:50:43 am
content: I'm pretty sure this is my power supply.http://www.jameco.com/z/JE215-Dual-Output-Adjustable-Linear-Regulated-Power-Supply-Kit_20626.htmlt was part of a competition I was in when I was in high school. One portion we were handed a kit and judged on time and quality. I used it for 25 years before my son burned up the transformer.