First Benchtop Multimeter Advice - Page 1
Forum section: electronics / beginners

author: itproman
author_rank: Newbie
timestamp: February 05, 2019, 01:23:11 am
content: I need it for general stuff and ham radio use,so don't need it to be too precise.So,first meter,preferably under $100 Canadian:I see on Ebay:BK Precision Dynascan Corp 2830 (radio museum puts it ca. 1988?)...HP 3435A....(same source,ca. 1977?)GW Instek GDM 8034 -can get 2 for $100,tested only for ACV and DCV,untested.Could be risky?Fluke?I know,as I see on this forum the HP 344401a is recommended.In any event,is it worth blowing money on such old technology?

author: 6PTsocket
author_rank: Regular Contributor
timestamp: February 05, 2019, 01:46:36 am
content: Quote from: itproman on February 05, 2019, 01:23:11 amIf it doesn't have to be that accurate why not get a hand held instead of a bench meter. There is a lot to choose from for 100 bucks. Plenty of new hand helds will perform better than many an old bench top.Sent from my SM-G900V using Tapatalk

author: 0culus
author_rank: Super Contributor
timestamp: February 05, 2019, 02:36:46 am
content: Quote from: itproman on February 05, 2019, 01:23:11 amI bought a ~1977 vintage HP 3455A for $150 last year. After fixing a contact issue in the main ribbon cable that connects the digital board to the display, it runs like a champ. What's more, it agrees with newer meters exactly (I am trying to avoid being a voltnut for my wallet's sake!) No reason to avoid older stuff. HOWEVER, keep in mind that older ones are bigger, heavier, and there's more likely to be age related problems (such as aforementioned contact issue, but also bad electrolytic caps).I also have a Fluke 87-V. The 87 gets more use simply because it's easier to move. But it's nice to have multiple ways measure when you're testing or building things, so I plan to get at least one more bench meter at some point.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: February 05, 2019, 07:31:23 am
content: Benchtop DMM's are excellent candidates for home brew solutions.With a power cord low power is not an issue.You can use big fat 7 or 16 -segment displays, or a TFT display.24 bit ADC's (With about 20 bit noise less resolution) are readily available.Use some microcontroller to glue everything together.Add some data output for logging to a PC, or uSD.Such ADC's can often sample upto a few ksps. (With reduced resolution). This is very usefull for extremely fast autoranging. You can have a stable readout in less time than it takes for your eyes to move from your probe to the display.You really do not need to spend more than about EUR 30 on components for such a meter.For the rest, save up some budget to buy a high quality handheld DMM as a reference to calibrate your homebrew device, such as a Brymen in the near EUR200 range. From what I know these have very similar spec's and reliability than the over priced Flukes. Why would you want to use a parasitic flatworm for measurements anyway? At best it's just luck if that meter functions properly.Skullcom has designed a simple mV meter with a decent ADC, (Open Source, Schematic and Source code on the 'net). but I would swap it with the ADS1220 with built-in reference voltage and PGA. But still a nice headstart to build a custom meter with the ranges and measurement functions which fit your personal situation. If you have the sourcecode it is for example trivial to add some linearisation functions for weird sensors.Those modern ADC's are so good that it is well worth to put relatively expensive resistors (low drift / tempco) in such a meter, and spend some extra time cleaning the PCB.Combine this with a few other relatively simple (but non trivial!) things and you have a very nice high speed 5 digit resolution meter and the biggest problem would be to calibrate it properly (Hence the EUR 200 Brymen).The good part is that if you've gone through the trouble of designing a PCB and some software then building 4 or more meters becomes trivial and cheap. Having a few multimeters is always nice for measuring various voltages and currents simultaneously. If you have multiple meters, then they also do not all have to have all measurement ranges. Why would you want 5 meters that can all measure resistances and capacitors?

author: rdl
author_rank: Super Contributor
timestamp: February 05, 2019, 03:11:55 pm
content: When I was restarting in the hobby 15 years ago, I bought a rebadged Mastech M9803R from RSR Electronics (just don't like the name "Mastech" much). I just wanted someting that would sit on a shelf without flopping around and falling all over the place, and run off mains power for as long as I wanted without shutting off. It has never given me any problems.If I was looking today, I might go for an HP 3468A, which is not as large as the other HP bench meters and can be found fairly cheap on ebay. It doesn't have a lighted display though, and that's a big negative to me.Another alternative is one of those VC8145 meters you can find on ebay. I may buy one just because it would be an upgrade over what I have now, not that I need one.https://www.ebay.com/sch/i.html?_nkw=VC8145

author: daveho
author_rank: Newbie
timestamp: February 06, 2019, 02:38:58 am
content: I find that if you're patient, good deals crop up on eBay from time to time. I scored a Fluke 45 for $80 US a while ago, fully working. Its accuracy seems decent, in that it agrees closely with the Fluke 8846a meters at my workplace. I've been happy with it so far.Dave

author: rsjsouza
author_rank: Super Contributor
timestamp: February 06, 2019, 11:16:06 am
content: I see some Keithley 197 meters for reasonable money (although I don't know what are the shipping costs). I have a 191 (similar form factor) that is crazily accurate (0.007% + 3d / 1yr) but not as featured as the 197. The HP3478A is another meter that can be had for reasonable money and is quite good.The advantage of older gear is that you can repair them if needed. Schematics are usually available and they tend to use commonly available parts.I also have a Racal Dana 5001 but for some reason it is quite difficult to see it in the wild for reasonable money.(edit) fixed typos and added accuracy details

author: David Hess
author_rank: Super Contributor
timestamp: February 06, 2019, 07:32:33 pm
content: Two things I would look for in a used instrument are full service documentation and simplified calibration. Some meters require difficult to find calibration standards and have difficult digital calibration procedures.Along the lines of what Doctorandus_P posted, it is too bad that there is not a fully documented kit for a 4-1/2 digital or perhaps better bench multimeter but the economics make an inscrutable handheld meter with greater functionality if not performance less expensive.

author: GreyWoolfe
author_rank: Unknown
timestamp: February 06, 2019, 11:42:00 pm
content: Quote from: rsjsouza on February 06, 2019, 11:16:06 amI have 2 of the HP 3478A and even scored one of them for $60 shipped!! The second one was bought for about $100 and is in calibration through Tektronix until April plus had the battery changed. The battery will probably need changed but it is well documented and the RIFA caps probably need changed, which is easy. As for calibration, OrdinaryMan1971 has graciously offered to the blog to calibrate the meter for the cost of shipping both ways. He did my first one. It took a few weeks because he is a very busy person and I was very happy for his efforts.

author: EEVblog
author_rank: Unknown
timestamp: February 07, 2019, 12:57:39 am
content: Why do you need a benchtop multimeter?If you just like the form factor, a nice Fluke 37 is simple and also battery powered portable.

author: EEVblog
author_rank: Unknown
timestamp: February 07, 2019, 01:00:08 am
content: Can't beat the price:https://www.ebay.ca/itm/Fluke-Multimeter-Model-37/153366536738?hash=item23b55ba222:g:7eQAAOSwLeFcN9Bi:rk:1:pf:0or make an offer, near new:https://www.ebay.ca/itm/Fluke-37-Multimeter-Multi-Meter-Works-Hardly-Used-Great-Condition/113614846755?hash=item1a73f8fb23:g:dWUAAOSwCNlcRPW~:rk:2:pf:0

author: tszaboo
author_rank: Super Contributor
timestamp: February 07, 2019, 01:37:34 am
content: You need a bench meter if you are doing automated tests, logging, or something that is constantly powered. Or higher accuracy than the handheld units. You will get more for your money if you buy a handheld DMM.I dont know, why anyone would want to buy a thirty year old benchtop meter, uncalibrated, with 4 digits or so, without any port that you have on a PC.