Cheap but useful Multimeter

[Danni BurnsParticipant @danniburns84841]

Hello

I am seeking your advice, please.

I admit that I am ignorant re. electronics, and today I needed to test a motor which I couldnt do.

Anyway, I would like to buy a cheap but not useless Multimeter – so I can start to learn about these things.

Can anyone suggest a useful & cheap Multimeter?

thanks in advance

[SillyOldDufferModerator @sillyoldduffer]

This one from Farnell is very similar to my basic “don’t care if I break it” instrument, which cost me much more than £4 twenty years ago!

Digital multi-meters are an example of a technology that’s become extraordinarily cheap.  Once the development cost of the chip was  covered, there’s very little inside.

Digital meters are easy to read, but take time to settle, which is why I also own a couple of analogue needle meters including a venerable Avo:  often as not seeing the needle kick is enough.

Possible to spend a lot of money on meters, but for getting started hard to beat £4, and go up market if needed later.

Or if money is no object, this inexpensive meter is yours for only £710!

Dave

 

[peak4Participant @peak4]

Hard to answer easily, particularly without defining “cheap”
Personally I have too many workshops and vehicles, and thus several meters.
Among them, an old AVO Mk7, and a couple of other moving needle meters, including ones for less than £5; all work OK, and I sometimes prefer an analogue meter.
Digital meters, I’ve a decent Fluke, Robin, and an old ex BT one, as well as a couple of Lidl/Parkside offerings.

Value for money, the Lidl one I keep in the Disco is probably the best; I guess about £10, and plenty accurate enough for most jobs.
N.B. I have seen a video warning that one of the Parkside meters shows 240V OK, but failed to register/display 1KV
Doesn’t bother me too much, as it’s for car, not high voltage use; one thing I’ve always been taught, test the test gear before relying on the readings.
i.e. Before checking if a tag is 240v live, I always check another one which I know is live.

As well as the meter, it also proves you’ve plugged the test leads in properly, and the wires are unbroken.
Cheap meters do tend to have less overload protection; 10A fast blow fuses often fitted to high end meters are expensive, and larger than conventional sized ones.

When my AC/DC clamp meter died last year, I looked at getting it repaired, as I wanted something to measure heavy DC amperages for automotive use.
I ended up with one of these, which, at the time, was £40 off eBay from a UK based seller.
It works well, if I had all my meters stolen, and needed a single replacement for general use, I’d likely look to get another one or equivalent; my only real complaint is the lack of provision for a croc clip on the test probe(s)

Bill

[Danni BurnsParticipant @danniburns84841]

Hi thanks

I am already learning a bit

Seems I need a CATII or CATIII (if I can get a decent (e.g. FLUKE) 2nd hand one cheap). I think £35 max. But Id be happier to pay <£10 for a CATII unit that someone has used and recommends.

 

I have seen these on ebay: Splinktech  DM2, Fafeicy XL830L, Hobby Digital Multimeter model M125 and Test Mate DMM-200

Are these similar to your Lidl? Are they to be avoided?

cheers

[Robert Atkinson 2Participant @robertatkinson2]

This little LAP meter from Screwfix:
https://www.screwfix.com/p/lap-dc-digital-multimeter-600v/793rt#product_additional_details_container

Is a good budget choice. More functions than the <£5 one and readilly available. It is also safer (CATII) than the cheap ones for mains use.

A good used choice recently were ex-MOD Fluke 25s These can be had for as little as £30 on ebay if you can wait for one to turn up at the right price (couple at around £50 at the moment).

Robert
Far too many multimeters here including 15 Flukes up to 6.5 digits….

 

 

[Danni BurnsParticipant @danniburns84841]

Thanks Robert

I just put a cheeky bit for F25

WHat functions do these not have that I would need? Fluke 101 Handheld Easily Carried Digital Multimeter 600 V CAT III (these are circa £60 new)

cheers

[Danni Burns]

On Danni Burns Said:

..WHat functions do these not have that I would need? Fluke 101 Handheld Easily Carried Digital Multimeter 600 V CAT III (these are circa £60 new)

 

For most purposes beginners need a meter that measures AC and DC volts up to, say 500 or 600V, resistance up to, say, 2 megaohms, and DC current up to 250mA, with a 10A range.  AC current is nice to have but pushes the price up, and may not be used much.

That requirement makes the Fluke 101 an expensive mistake. If I read the spec right the 101 doesn’t measure current at all, so 0/10 in my book.  It measures up to 40Mohms, capacity (farads) and frequency, all unlikely to help a beginner. Other Flukes do meet all basic requirements, but check the specs.

Throwing money at meters gets you some combination of improved robustness,  accuracy, and resolution, and/or auto-ranging, auto-shutdown, higher CAT rating, AC current, wider ranges, and maybe inductance, capacity, diode, and transistor testing.  If you don’t know yet why these are worth having, start with a basic instrument, set the range manually and remember to turn it off.

At this stage best avoid chasing ‘quality’ unless you have a specification.   The cheap meter I pointed at does the basics, and, if it has limitations, understand them and then go upmarket as necessary.  The ex-MOD meters recommended by Robert are excellent provided they are in good condition.   Solidly made for a reason: servicemen bash them about, so secondhand is a risk…

Dave

[noel shelleyParticipant @noelshelley55608]

For working with AC motors – single phase, being able to read the value of capacitors is very useful. Though whether you can get this function to read high enough for this type of work on a cheap one ? Noel.

[Robert Atkinson 2Participant @robertatkinson2]

Danni,
As Dave SOD says the fluke 101 is lacking a current range.
The <£30 LAP one I suggested is actually CAT III , not II as I said (the more expensive one is II). It’s priary limitation is no low voltage AC voltage ranges but the 200 V AC range has a resolution of 0.1V so good enough for 90% of applications.

I really can’t recommend the <£5 models for any kind of mains measurement except a quick check at a socket. They really don’t meet the safety requirements regardless of markings.

I’ve not had a faulty Fluke 25 yet from ebay. As long as the condition is “used” you are covered by ebay seller protection.

Robert.

[Danni BurnsParticipant @danniburns84841]

Thank you for all the advice.

I made an offer for Fluke 25 – awaiting a reply. I can buy the LAP any time and will probably get that and just play about with it to find its limitations – as suggested.

 

[Russell EberhardtParticipant @russelleberhardt48058]

It does depend on your requirements.  I have an accurate one for precision measurements but a cheap and cheerful one for everyday use.  The most common use for the cheap one is testing batteries.  Surprisingly the next most common use is temperature measurement with the supplied thermocouple.

Russell

[Danni BurnsParticipant @danniburns84841]

Thanks Russell

Can anyone comment on Fluke 73 (eBay item number:306095055731), 75 (eBay item number:176830873089)?

Are they any use to me or limited like the fluke 101 that Robert commented on above?

Thanks

[Robert Atkinson 2Participant @robertatkinson2]

The 73 is looking like a good buy at the moment. The 75 is getting a bit high in price. They are both excellent meters and better than the 101. The 75 has a hold function and slightly better accuracy but that makes no differernce to your needs. They are smaller, lighter and slightly less accurate than the 25.

Robert.

[SillyOldDufferModerator @sillyoldduffer]

Those Fluke’s both meet my minimum requirements so should be OK.   One thing to watch out for is that they come with a set of test leads AND that the leads are in good condition.  The CAT rating of the meter won’t save you if the leads are damaged!  Spare leads can be bought, but they ain’t cheap!   When I lost a lead in the street founf it was cheaper to buy a new meter than to buy a set of leads.  Robert will know if Fluke test leads have common sized sockets or are unusual.

What the meter is to be used for matters.   I rarely test for mains with a meter because poking about with test probes is quite risky.   Better to use a mains-test screwdriver, Screwfix about £6, or a socket tester, about £8.   For that reason I don’t worry about CAT ratings: I would if my metering involved a lot of high-voltage work.

A lamp on a pair of fly-leads is useful too.

An oscilloscope is often far more useful than a multimeter for investigating amplifiers, digital circuits, and motor speed controllers.   You can see waveforms, capture events, and take a wide range of measurements.  In my youth oscilloscopes were unaffordium, but plenty of choice these days.  Maybe something like this £65 Hantek PC plug-in as a ‘get you started’ tool.

What exactly do you plan to do with the meter?  I’m assuming something basic, which doesn’t need a capacity range, but might be useful for checking single phase start/run capacitors.    Inductance is useful for ham radio.   Some need very high mega-ohm ranges, others measure very low resistances, less than 0.1ohm.  If AC current is important, look very carefully at the spec.   Ditto if the meter has to measure ‘true RMS’.   Some need high accuracy, for others 5% is ‘good enough’.   0.5% is costly.

Most hobbyists don’t need a Fluke quality meter, and are unlikely to buy a new one – too pricey!  Condition matters much more than the brand-name when buying second hand, and a 20 year old meter may not be a bargain…  On the other hand, they are well-made to resist abuse.

Dave

 

[Robert Atkinson 2Participant @robertatkinson2]

Fluke hand held DMMs are compatable with standard 4mm sleeved safety plugs. The only exception I know of is a version of the 8022 that was made for BT that takes a non-standard long plugs. They have a raised bush around the sockets so are easy to spot.
The OP is looking to fault find a mains motor circuit so 240V measurement is required.  A good low resistance range (200 ohm) is useful too.
The little £10 LAP  from Screwfix is still a good option.

The use of the old “neon” test screwdrivers is really not acceptable these days. They do not protect from surges etc. No CAT rating. The modern, safe, alternative is a non-contact electronic detector. Its really unbeliveable that they can sell a neon screwdriver for £6 when you can get a DMM for £10 or a non-contact detector AND a socket tester for £15 https://www.screwfix.com/p/lap-ac-voltage-detector-pen-socket-tester/5449h
Not applicable to the OP’s issue but ideal if doing basic electrical maintenance around the house like replacing sockets.

Robert.

[Danni BurnsParticipant @danniburns84841]

Hi dave/Robert

I do have a non-contact electronic detector.

The immediate problem I have is testing a 12v motor, inside a drill doctor bit sharpener. It has an emi filter. I was advised that I could test if it’s just the emi filter by testing if the motor works – if i had a tool. Note: all of this is news to me. I know nothing about electronics.

So I’m changing both the emi and motor. possibly costing me £25 because of my ignorance.

I attempted to test/run the motor with a car battery charger. It didn’t work anyway, and I didn’t electrocute myself. Was this even a valid test?

Hence, my decision to not so ignorant next time.

I have a couple of desk lamps 240v that need attention also.

Cheers

Danni

 

[Danni Burns]

On Danni Burns Said:

…I attempted to test/run the motor with a car battery charger. It didn’t work anyway, and I didn’t electrocute myself. Was this even a valid test?

… 

Yes, assuming the battery charger can provide enough current, which it probably can.

That the motor didn’t stir is probably bad news but have a look at the brushes.   Will be obvious if they’re badly worn.  Also make sure the commutator is clean and undamaged.

Motors often fail if worked too hard for too long.  The windings get hot enough to destroy the insulation resulting in shorted turns.   Or corrosion/vibration has broken a connection inside.

If power reaches the motor with the filter in circuit, and the motor doesn’t turn, then the filter is OK.   Unless they fail open or short circuit a multi-meter won’t help much.   It’s safe to disconnect a filter – they short electronic muck to ground, a very good thing, but the motor will work antisocially without them.  If suspected of being faulty, just replace it.

Useful clues that  a motor is done for when power is reaching it are blue smoke and getting hot.  Or nothing at all.   Worth having a look inside, but it’s usually easier to replace than repair.   Older motors tend to be easier to work on than new ones, which might be riveted, clipped or welded together.

Beware spending £50 on a Fluke meter to save money on a £28 fix!   However, meters pay off the more they get used, or for educational reasons.    And if you own one it will probably get used!

Approach the desk lamps with caution.  Whilst 12v is almost entirely safe 240vac is potentially deadly.   A little understanding reduces the risk considerably.  A shock received whilst testing on a dry wooden floor is much less dangerous than the same shock received whilst stood on a slightly damp concrete floor.  And better to test the lamps for continuity with the meter’s low ohms range rather than plugging them in and poking about for high voltages.

In these situations I ask myself ‘is this dumb, dangerous or different?’   Dumb might be because “I don’t understand this yet”.  Dangerous as in “could I end up in hospital, A&E or the morgue?”  and Different as in “Is this new and untried, and outside my experience”.   Professionals often break the dumb rule by taking unwise shortcuts – acting thoughtlessly under pressure or whilst unwell.

Have a go though, just be careful with mains!

Dave

[Master of noneParticipant @masterofnone]

I agree regarding the test leads.  In my experience, very cheap meters have low-quality insulation on the test leads which tends to crack close to the connections to plugs and probes long before the meter fails.  The exposed probes are often longer than the 2-4mm recommended by GS 38 for working with voltages above 50 V.

My Megger installation tester has interchangeable ends on the test leads. See https://www.tester.co.uk/megger-mft-multifunction-test-leads

As Dave points out, they are reassuringly expensive, but if you are working on mains voltages, the quality of the test leads is an important consideration.

[Tim StevensParticipant @timstevens64731]

One factor which needs thinking about – when you say ‘battery charger’. Modern clever chargers actually look for a real battery, and do not switch on if you are using the charger to power or test a non-charging device, such as a 12v motor.

What you need for this test is an old fashioned charger which comprises a mains transformer and a rectifier – nothing more.

Hope this helps

Tim Stevens

[Danni BurnsParticipant @danniburns84841]

Thanks MON and Dave

Tim – I was questioning if the charger even worked. So I think you are spot on.

cheers

[noel shelleyParticipant @noelshelley55608]

Tim has it ! A modern charger will only work on a slightly discharged battery – it is NOT a power supply. Try a car battery or other source of 12v. Noel.

[Danni BurnsParticipant @danniburns84841]

Yep. Thanks Noel

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