Which Digital Multimeter?

[MrBungle]

Originally Posted by DonaldStott

MrBungle - your recommended Signstek UNI-T UT61E looks like a real bargain despite some concerns about build quality etc. Not sure what you mean by "22,000 count, true RMS, continuity without lag unlike the 115" - sorry?

22,000 count is the display resolution. It uses a digital counter inside so it is know as the count. From a display perspective that means it can display 2.1546v or 21.954 volts for example which is relatively high precision. However for frequency measurements that's not all that good hence my comments. 10.700 MHz for an IF isn't necessarily enough resolution.

True RMS. AC voltage is measured in RMS (Root Mean Square). That is fine if the AC voltage is a sine wave. Sometimes it might be a square wave, some times it might be a distorted sine wave in some way. At that point the RMS voltage is different. This meter can work that out for you. Some of the cheaper ones don't.

Continuity without lag. When you use the continuity beeper, on some DMMs there is a delay between when you probe and when the beeper goes off which is annoying as it feels like the contacts are bad. This meter doesn't have that delay. The 115 does have a delay. It's not too bad but it would annoy me at least. I might just be fussy

[paulsherwin]

You can build a simple signal injector from junk box parts - it makes an excellent beginner's project. Any silicon transistors will work. See http://www.instructables.com/id/Tic-...gnal-Injector/

[Craig Sawyers]

I've scrutinised the ebay image above, and for what it is worth:

The CE mark looks correct, ie it conforms with the CE logo.
It says under the CE logo that it is CAT II, 600V, so could be used to measure mains voltage at a socket, or inside an instrument under test.

The provisos are:

The CAT level is not part of CE approvals, and should not be printed near that. It should be moulded into the plastic at the terminals to which that level applies.

The instrument has CAT II 600V on it, but the write up says it can be used on CAT III circuits; which is it? The probes shows definitely are not CAT III compliant.

But hey - it is fifteen quid. But just be aware that if you get it wrong (watch the Fluke video!) and put voltage up the current terminals you might be holding onto a bomb.

Toolzone, though, is a real company - I have bought one or two of their woodworking tools, and found them to be excellent.

[julie_m]

A couple of £5 street-market DMMs and a first-generation battery hand-held oscilloscope are probably going to be as good as any of the test equipment that was available to most radio and TV repairers back in the days.

The most important thing about test equipment is that it should be comfortable (which is highly subjective), because you're going to be using it all the time.

In this thread https://www.vintage-radio.net/forum/...d.php?t=129590 I was looking for a DMM and got this one https://www.rapidonline.com/voltcraf...imeter-51-5689 it is very good.

[Bazz4CQJ]

Originally Posted by Craig Sawyers

Well, all that Fluke stuff I've been batting on about is hobby use. It is the tip of an exceptionally large obsession iceberg with test equipment.

But you're right - I spent my career in professional electronics, in a very broad sense. And as I get older, I become more determined to get older still and not vapourise myself!

Ah... a hobby within a hobby, and that is your perogative and I trust it gives you great pleasure. Reminds me a bit of my VCM163 valve tester, which I hardly ever use, but don't plan to part with, even though I'm sure its value is now falling appreciably .

B

[Craig Sawyers]

Well, I've said my piece relating to safety, given some links which show the tendency of cheapo meters to self-immolate if even slightly abused, made some suggestions, and pointed out the inconsistency of Chinese specs.

I can do nothing more on this thread; if you want to spend not a lot, that is entirely up to you.

As a parting shot to this thread, here's an Australian's guide to buying a decent multimeter that is not going to break the bank https://www.youtube.com/watch?v=gh1n_ELmpFI

[MrBungle]

Originally Posted by Craig Sawyers

Well, I've said my piece relating to safety, given some links which show the tendency of cheapo meters to self-immolate if even slightly abused, made some suggestions, and pointed out the inconsistency of Chinese specs.

This is definitely true however there is an analogy which can be used here: you can drive the safest car on the world but you'll still kill yourself if you drive it into a wall or someone else hits you head on at 100mph.

Ergo, most of the risks that are injurious with electricity seem to result from the device under test, probes or human stupidity. The meter is incidental and is a small risk compared to the greater ones. If you can afford to not ignore it, definitely do it but concentrating on the greater risks has a better return.

I speak from experience having zapped myself numerous times, never because of equipment but because of me

[Radio Wrangler]

In those famous words, "What could possibly go wrong?"

It is unlikely that a bad multimeter would kill its user. Crappy test leads are a greater risk They are in your hands when you make measurements on mains etc.. Unlikely or not, most people have a very strong preference for it not happening. This is something on which we each must make our own decisions on what precautions are sensible.

Much higher up the scale of probability, bordering on certainty, is the likelihood of probing some power circuit while set to Ohms or Amps. A well-designed meter will survive, maybe unscathed, maybe with a popped fuse. However, the cheapies are so much cheaper you could buy several for the cost of a good one.

I bought an old Fluke 8060A at an amateur radio rally for £20 about 18 months ago. It works nicely, and replaced the ITT/Metrix multimeter I carried in the car until its LCD went bad. This instrument is a 20,000 count job, and does true RMS. It doesn't test diodes or transistors or capacitors. It does have a frequency counter function, but like most multimeters with this, it's pretty much useless. Capacitance measurement in multimeters is usually pretty limited in range.

So I have a separate frequency counter (few Hz to 520MHz)
I have a little peak LCR meter for quick checks, and Wayne-Kerr bridge for serious work.

In the radio shack I have a Fluke bench meter, but I usually use a wavy-pointy AVO EA113 because I like it. Mostly I look at voltages with an oscilloscope.

I'd suggest you go for a plainish multimeter. Forget bells and whistles and go for something dependable. Use separate instruments for the less mainstream tests.

The old saying jack of all trades and master of none applies here.

The HP/Agilent/Keysight instruments are engineered to comparable standards to Fluke, but lack the brand-leader price boost. I have a liking for classic HP gear, but I'm biased... I used to design it.

David

[mhennessy]

Craig is quite right to point out the safety concerns with cheap meters. And yes, better meters will hold their calibration for much longer.

If you don't want to spend a fortune on the meter, please consider upgraded probes. These will make your life better (not just safer). Budget around £20 for these.

I have a Fluke collection, but most were bought second hand, and with luck and patience, most were bargains. Because they are so well made, buying second-hand is relatively low-risk compared to many other types. The new prices are certainly steep, and not always justifiable for a hobbyist. But if you like the idea of a new Fluke, you can find the Fluke 107 on eBay for around £50-60. That model was made for "emerging" markets and isn't officially distributed in the UK, but it's still a good meter (and comes with nice probes). The main feature it lacks is "True RMS".

Yes, the 115 only has 1mA resolution on current. The 116 has a uA range. Having just tried it, the speed of the continuity mode seems to be up to the usual Fluke standards.

The Fluke 25 can be found for around £30 second-hand (usually ex-MOD), and this can be confidently recommended as a bomb-proof option. The contemporary 70-series models are quite a bit smaller, but seem to command much higher prices.

New, I'd also recommend the EEVBlog Bryman. I have one here, and it packs a lot of functionality into a small case. Perhaps a little too much at times, which leads to a few ergonomic quirks. It comes with upgraded probes, which are really nice.

Coming down the price range, the RS Pro 14 is pretty good for less than £20: http://uk.rs-online.com/web/p/digita...eters/8937896/ - at that price, you could pick up a couple. The probes are "passable". Or even cheaper still, the Bside ADM02 uses the same chipset as the RS unit, but the probes aren't very nice (a bit inflexible). I reviewed these 2 meters here: http://golbornevintageradio.co.uk/fo...d.php?tid=5501 - the bottom line is that they're excellent for the money, and a lot better than the super-cheap manually-ranging meters that I really wouldn't touch. These meters aren't True-RMS, but all feature uA ranges.

Ultimately, what you're buying in to with meters like Fluke is confidence. The cheaper meters are fine if you're careful with them, and only use them in low-energy situations, and don't make any mistakes (you can connect a Fluke to the mains when set to Ohms mode, and it won't complain - do that to a cheap meter, and it'll die). Cheap meters will drift with time, even if not abused, but at least they have trim-pots, so can usually be brought back into spec.

Arguably, it's often better to have 2 or 3 meters rather that 1 expensive one. There are plenty of situations when you need to measure 2 things at once, and having more than one meter means you can check them against each other.

[MrBungle]

A +1 for new probes. Also inspect them regularly.

Also regardless of the equipment in use: high energy, high temperature, clipping leads, anything. Wear safety glasses! Most things heal easily. The eyes not so much.

Edit: stuck my DT830 across the mains in ohms and it blew a fuse. Turns out it had fuses in it. Some of them don't!

[G0HZU_JMR]

For vintage radio and test equipment repair work you may need a meter that can measure high DC voltages and some of the meters mentioned seem to have a 600V limit. In my case, I rarely measure high voltage directly on any of my DMMs and would normally use a divider probe but all of my DMMs show 1000V DC max on the front. One says 1400V DC but none of them are limited to 600V DC across the input terminals. What if you probe something higher than 600V by mistake?

Some of the older/popular HP bench meter models are limited to 300V DC across the terminals. For modern solid state work this is rarely going to be a problem but I think I would select a meter that can tolerate 1kV DC if I was going to be using it on a variety of vintage gear.

ie it conforms with the CE logo

The CE logo specification has no tolerance on the size/shape so technically it can be anything. Back on topic, if it looks and feels well built it probably is (that costs money, unlikely for a bad instrument).

[evingar]

Originally Posted by mhennessy

Craig is quite right to point out the safety concerns with cheap meters. And yes, better meters will hold their calibration for much longer.

//

The Fluke 25 can be found for around £30 second-hand (usually ex-MOD), and this can be confidently recommended as a bomb-proof option. The contemporary 70-series models are quite a bit smaller, but seem to command much higher prices.

I'd agree with this - I use a Fluke 25 as my main meter and I've got an ex military New Old Stock one in line for when it packs up (It's already been a long wait and no sign of it being needed any time soon). My current one has received electrical and physical abuse that would have finished any a lesser meter off. The internals have decent clearances and fusing that makes me confident that I would be really well protected in the event of me doing something catastrophically daft !

It's the safety issue that weighs with me more than anything. I repair PSU's as well as vintage equipment and I wouldn't dream of putting an "el cheapo" Chinese meter anywhere near the primary side of those.

I agree that experience of the "day Job" also colours attitudes to the quality of Test Gear. In my case working at a "Big Physics" installation focuses my mind somewhat on the safety side of things.

[Craig Sawyers]

Originally Posted by merlinmaxwell

The CE logo specification has no tolerance on the size/shape so technically it can be anything. Back on topic, if it looks and feels well built it probably is (that costs money, unlikely for a bad instrument).

Not true - it is very, very precisely defined. The minimum size on a product is also defined.

[Craig Sawyers]

Originally Posted by Radio Wrangler

I bought an old Fluke 8060A at an amateur radio rally for £20 about 18 months ago.

I have four; three of which are pre CAT rating, and one that is post CAT. The formal spec of the 8060A is a measly CAT I. So you can only use them for low voltage circuits inside equipment. It is not rated for connection to mains voltage anywhere. And yes - I was surprised.

[ionburn]

Not sure if it has been mentioned in the various replies but one thing to note is that if you are using old service literature for servicing then the voltage reading etc will likely be given as read by (typically) a 20kOhm / Volt meter (eg AVO 8) so using a digital meter will usually give different readings. These may differ radically from the service literature. Ok if you realise this but it is still useful to have the equipment from the day. Although I use a digital meter most of the time I would not be without my analogue equipment which will sometimes give a far clearer indication of what is happening

[Radio Wrangler]

Originally Posted by Craig Sawyers

I have four; three of which are pre CAT rating, and one that is post CAT. The formal spec of the 8060A is a measly CAT I. So you can only use them for low voltage circuits inside equipment. It is not rated for connection to mains voltage anywhere. And yes - I was surprised.

I think that means it's not compliant with current safety standards for mains measurements, but the unit was specified for such use. It's probably nothing more than having simple 4mm sockets rather than requiring the interlocking skirt type. Plain bananas just aren't idiot-proof enough. Classic AVOs will fall into the same category - only safe if you use them right.

David

[Philips210]

Hi

My main multimeter is a Fluke 23 Mk1 bought new in 1987 for £170. As mhennesy points out they are exceptionally well made. My meter has had continuous daily use for nearly 30 years and has never let me down. I have only had to replace the leads/probes on a couple of occasions. I think the model 23 (sporting a yellow case) was termed intrinsically safe. This meter is based on the 70 series but I'm not sure of the exact model, possibly the model 77.

I also have a few other Fluke meters in my collection and they are also a pleasure to use. The calibration on these meters seems to be very stable which gives you a lot of confidence when making measurements.

Regards
Symon.

[julie_m]

Both analogue and digital instruments have their strengths and weaknesses. At least one of each type is highly desirable, but even the "wrong" sort for a particular situation is always better than nothing.