Multimeters

[Kyburo]

Hey

Being a clearly very hands on bunch here, along with a fair number of engineers I'd imagine, seemed like a good place to ask about multimeters.

This is another "I'm new" post really, I've not owed one before, and always ended up using other peoples during my studies. I've currently got a headphone desktop amplifier on which the USB connection seems to have died a few years back. Rather than pay to send it back to China I'm hoping to look myself and track down if there are any issues on the circuit board (which is easily accessible).

Anyway, before having a root around online I thought I may as well ask if anyone has any recommendations for something on an introduction level/brands to go for or stay away from etc.

Cheers!

[Thomas Klemm]

EEVblog #597 – Fluke 114 Kit Multimeter + Sparkfun/Fluke Rant
His video-blogs are always funny and informative.

Hope it's useful
Thomas

[jebem]

Hi,
It all depends on what are your needs really.
Assuming that a low cost general purpose non professional equipment to pick around low voltage electronic circuits is what you are looking for, I would say:

1) Any brand is OK.
Fluke is a well know brand, but their low cost equipment is not on pair with its high end professional line.
So at the low end, any brand will do, but I would selected a Japanese or Korean brand for the best bung for the money.

2) I would like to see these features included in the core specs:
- handheld compact equipment
- 3.5 digits at least
- DC and AC voltage auto range from 2V fs to 200V fs at least
- AC voltage with decibel reading as a optional feature if possible
- DC current for micro-amperes reading
- DC current mA and Amperes auto range (up to 2 Ampere if possible)
- AC current mA
- Resistance auto range for usual readings like 2 ohm fs up to 20 Mohm fs
- Continuity tester with sound
- Diode test
- Test leads as required

3) Nice extra features to have:
- Capacitance readings for usual values like 2nF to 200 uF
- Inductance readings for usual values like 2mH to 2H if possible
- Signal generator, square wave is OK, at least with 1KHz and 2KHz frequencies
- Transistor tester at least for bipolar npn and pnp types
- AC voltage reading up to 20KHz frequencies at least

EDIT:
4) One of my nice kind of vintage (1996) multimeters (the specs can be checked on the link below):
Protek 505 from HUNG CHANG, SEOUL, Korea
http://www.radiomuseum.org/r/hungchang_d...k_505.html

and a similar model, the 506 is selling right now (I have nothing to do with this sell!)

[Garth Wilson]

(09-12-2014 10:11 AM)Kyburo Wrote:  I've currently got a headphone desktop amplifier on which the USB connection seems to have died a few years back. Rather than pay to send it back to China I'm hoping to look myself and track down if there are any issues on the circuit board (which is easily accessible).

Since they want to address the European market, they make things with lead-free solder which is not reliable. You probably have cracks in the solder at one of the connectors, connectors that should not be surface-mounted anyway because of the stress they get on them. I have a IDE-to-SD-card interface on an old PC, and the connector for the SD card quickly went south. I re-soldered with leaded solder. That was the end of the trouble.

[Katie Wasserman]

(09-12-2014 10:11 AM)Kyburo Wrote:  Anyway, before having a root around online I thought I may as well ask if anyone has any recommendations for something on an introduction level/brands to go for or stay away from etc.

I'd first ask what your budget for this is? You can spend anywhere form $5 to $5000 and mostly you get what you pay for as far as quality goes, less so for features. You can spend $30 for a meter with all sorts of features but it's not likely to be reliable, accurate nor safe. If you ever plan to use this meter on high voltages safety is very important and one of the major cost factors. The other major cost factor is accuracy.

[Maximilian Hohmann]

If you are interested in vintage calculators, you might consider buying a vintage multimeter for them :-) As with calculators, I prefer luminous displays in multimeters as well. There are still quite a lot with LED and Nixie displays being offered on eBay for decent prices. Many of them are professional calibrated units that were enormously expensive when they were made in the 1970ies. Even HP multimeters are easily found, but most of them are large units for 19 inch racks.

The one I use most often is a late 70ies or early 80ies from Philips (PM 2517E) with LEDs that can be found for around 50$/€/GBP. An interesting model is the Sinclair PDM35 that resides in a small calculator housing and has a very unusual purple LED display. In similar shape but slightly larger comes the "Schneider DIG.500" from France with Nixie tubes. Unfortunately it only has three digits.

[Kyburo]

Thanks for the responses.

In a week I'll be a student again, after leaving the working world to study mecheng

So with this in mind, something that isn't going to break the bank, but I suppose my main concern would be reliability. I generally am willing to pay extra for something if it'll survive much better than the cheaper option and so tend to buy things with an aim to keep them for life, or at least until I require something with extra features because my need is suddenly more serious (work or hardcore hobbying).

Usage will really be just for mini projects and diagnostics on bits and bobs that fail for friends and family.

Budget wise, I'm in the UK but roughly converting I'd say like $50 or less ideally, but up to $150 if it's really really worth it.

In terms of vintage or new, I'm actually not fussed, as long as it's reliable I'm as happy with old solidly built kit as new, but just want to make sure it's the kind of thing that'll just keep going. Safety wise, I'm not planning on using this device to test anything of a dangerous level, but I suppose I'm not 100% certain where the danger level comes in - are we talking danger to the device melting, because that's a given to my knowledge of multimeters if you use it on settings with resistances too low for the power flowing - or are we talking actual danger to the user?

Also a side note, any advice on soldering irons would also be handy as I've previously used my grandfathers but I now live many hundreds of miles away - same deal with this also, willing to pay extra for something that'll last.

EDIT: Cheers Thomas for the EEVblog link, I watched that vid and then also went on to find his post #75 beginners buying guide... I'm starting to get more of a sense about the safety concerns (college electronics with everything at 1.5V doesnt quite give you the same realisation). I'd assumed products would have to be of a higher safety standard before it was legal to market them!

Also the chap presenting, definitely making me laugh, he isn't too keen on cheapo multimeters.

[Garth Wilson]

Quote:Budget wise, I'm in the UK but roughly converting I'd say like $50 or less ideally, but up to $150 if it's really really worth it.

$50 is kind of the threshold for anything I would recommend.

Quote:Also a side note, any advice on soldering irons would also be handy as I've previously used my grandfathers but I now live many hundreds of miles away - same deal with this also, willing to pay extra for something that'll last.

I've soldered probably tens of thousands of joints, and I'm not impressed by the high-priced temperature-controlled ones that are usually not hot enough to do a good job. It was a case where higher price does not equal better. It was a surprise to our production people when I showed that soldering a plastic switch years ago resulted in less melting and damage if they would use a hotter soldering iron so as to be able to complete the job so quickly there wasn't time for the heat to reach the plastic before everything was cooling again. I go for the Weller irons where you buy the separate handle, heating unit (33W), and tip (usually a chisel shape). I think a set comes to something like $50-$60, and you provide the base separately, even if home-made. One thing I don't like now though is that the tips they're selling are RoHS and they don't last like the non-RoHS ones did years ago.

If you really wanted a vintage meter, you could get a mechanical one with the needle and all the scales.

[Dave Frederickson]

Jose mentioned some nice features to look for. One he forgot to mention is a frequency counter. Even my little Fluke 112 has that feature. Buy you will soon learn that there are some things you cannot measure with a DVM. You will need to observe signal characteristics and yearn for an oscilloscope.

Might I recommend the Dick Tracy Oscilloscope Wristwatch.



Okay, it's not Dick Tracy, but it's pretty geeky.

Dave

[Maximilian Hohmann]

(09-13-2014 12:38 AM)Dave Frederickson Wrote:  Okay, it's not Dick Tracy, but it's pretty geeky.

Very cool :-) I want one! But I wouldn't dare to connect any signal above 12V to it...

[Kyburo]

Hahaha! Well not quite what I was expecting, but clearly it'll give Apple a run for it's money as they move into the wrist market.

I've been quoted $50 for the repair of my headphone amplifier, not including shipping to China. Being that I could instead get a multimeter and soldering iron for the total cost of perhaps $100 it does seem worth while.

After watching a load of videos from EEV and Martin Lorton I'll probably end up going for one of these chaps: http://www.uni-trend.com/ut61e.html

I can get for around £40-50 depending on if its shipped from China or the UK. It does (as far as I can tell) have a load of features Jose recommended like the voltage, current and freq ranges; diode testing; auto hold; capacitance testing (although not quite down to 2nF); continuity testing.

Unfortunately no signal generation that I've seen, and perhaps not the best protection judging from the various video blogs but having said that I'm not planning on using this on anything above 240V mains in the future, and certainly not straight away! It'll mainly be battery powered items, or 240V mains items like my headphone amp when they're unplugged (although still potentially with a fair amount of charge stored). It does also have PC logging, no idea if I'll ever use that but hey!

Not yet pulled the trigger, but seems worth while getting a bit more electronics hands on under my belt and spending the same cash on this meter and a £20 soldering iron or so. Again, thanks for the advice.

[jebem]

(09-13-2014 08:30 PM)Kyburo Wrote:  After watching a load of videos from EEV and Martin Lorton I'll probably end up going for one of these chaps: http://www.uni-trend.com/ut61e.html

I can get for around £40-50 depending on if its shipped from China or the UK. It does (as far as I can tell) have a load of features Jose recommended like the voltage, current and freq ranges; diode testing; auto hold; capacitance testing (although not quite down to 2nF); continuity testing.

Unfortunately no signal generation that I've seen, and perhaps not the best protection judging from the various video blogs but having said that I'm not planning on using this on anything above 240V mains in the future, and certainly not straight away! It'll mainly be battery powered items, or 240V mains items like my headphone amp when they're unplugged (although still potentially with a fair amount of charge stored). It does also have PC logging, no idea if I'll ever use that but hey!

Looks good enough and well above the average low end multimeter offerings.
And the PC logging interface to a PC is really handy for specific diy projects!

As you say, it misses the signal generator, but you can build a nice simple one as a small diy project.