Digital multimeters

[dbishopbliss]

I just got an electronics catalog today and it has a number of benchtop True RMS multimeters in it.  I bought my multimeter at Radio Shack 10 years ago for probably $20 or less.  I'm wondering what advantage a $200+ meter has.  Should I put one on my Christmas list (planning early).

[JC]

Boy, as far as accuracy is concerned, I really can't say if there is much of a difference.  For the most part, "Benchtop" seems to always be more expensive than portable.

I like a meter that handles more complex AC waveforms than just sine waves, but I really can't say what specs describe that ability.  The ability to accurately measure AC riding on top of DC is good, too, but again, I don't know what spec describes this.

You might see something that has additional features you might find useful.  Recently, I would have liked a meter to check a high Voltage diode out of a microwave oven; turns out most meters don't supply enough Voltage to turn one of those on.  I have a meter with the capability to test frequency in the audio bandwidth which is useful, and it also has a limited range of capacitance reading; it won't check capacitance at anything near operating Voltage, though, so it is pretty limited.

If I was to go for something strictly for use on the bench, though, I think I might opt for one with a large LED display so that it is easy to read from a distance and at an angle.  LCDs are great for saving batteries, but if saving batteries is not the issue, then big and bright is preferable, IMO.

[Paul Joppa]

In some cases, a "true RMS" meter will also have a wide frequency range. My ancient Fluke is good to about 100kHz - most meters don't give decent AC readings above a few kHz.

True RMS gets you the effective heating value of current even when the load is nonlinear. Mostly useful to check power consumption of an amp, or the heating load on a power transformer winding where the rectifier/filter is quite nonlinear.

A low-ohms range, like 20 ohms full scale, is useful for checking transformer windings and speaker voice coil resistances - but I don't think there are any such these days for less than $2000.

I don't trust inductance meters for audio devices, they are designed to measure RF components. But I do use the capacitance measurement sometimes.

My two cents.

[JC]

My Fluke 26 has a 40 Ohm range, at only a couple of hundred dollars; of course, I have no real idea how accurate it is, especially right of the decimal!

[Grainger49]

That auction site has good used Flukes that are true RMS reading for under $80, sometimes going for under $50. 

[Paul Joppa]

My Fluke 26 has a 40 Ohm range, at only a couple of hundred dollars; of course, I have no real idea how accurate it is, especially right of the decimal!

Cool! Excellent news; I'd given up looking some years ago.

[2wo]

No, you probably don’t need it. I have a number of meters. My favorite is the Fluke 87. Easy to use and that is what work provides. A few years back the rules changed and any tool that I use that makes a measurement has to be calibrated every 6 months. So I send in my meter, pipettes and a host of special tools, as well as my 6" Starrett rule and an NITS 100mg calibration weight…I think I am in the wrong line of work.

But anyway. My old pre cal meter never varies from the freshly blessed one by more than nothing.

I had another point to make but I am too tired I’ll get back to it…John     

[JC]

Well, Paul, now I'm wondering if the 26 is even still available.  IIRC, it was the "ruggedized" version of a 77, and came with flat-sided probes for easy insertion into outlets.

I think the 77, at least, is still available, though it must be up to model IV or V by now.

In either case, they claim accuracy to .1 Ohm, and I will say that the 40 Ohm range, which is also the range with the audible continuity beeper, has been very useful.

[Ritchie]

Another thing to consider is safety depending on your budget.
As you get into the better meters they will have a fuse in the current circuit. A very good safety feature in case you ever accidentally check voltage while on the current circuit.
Check for this when looking as it is a very important safety feature especially if you are using the meter for current and voltage measurements. If your not sure ask the seller if it has a fused current circuit or check the specs on the manufacturers website.

Thanks,
Ritchie

[Maxwell_E]

I can't recommend Fluke meters enough. Lifetime warranty, great accuracy. I've never seen one break except for one guy who tried to measure 6kV without a high voltage probe. They're pricey, but even the 115 base model has great features and it'll last forever.

[JC]

So very true.  The meter I referred to above has a separate 10 Amp current range which uses a separate fuse and even a separate input jack.

My only regret is that the 10 Amp fuse is a cartridge that is not readily available at Radio Shack or the hardware or automotive store.  I either have to mail-order it or pay an astronomical price at the local parts "distributor".

So, it pays to check the fuse type your meter uses and keep a spare in stock!

[Grainger49]

I can't recommend Fluke meters enough. Lifetime warranty, great accuracy. I've never seen one break except for one guy who tried to measure 6kV without a high voltage probe. They're pricey, but even the 115 base model has great features and it'll last forever.

My reply #4 suggests buying used.  You pay $50 to $80 for a meter you will use the rest of your life and it is a good deal.  You will never have to buy another.

[denti alligator]

I'm replying to some advice given in the thread on essential tools.

Where can I get a used Fluke for close to $50?  Ebay certainly doesn't seem like the place.
Money is an issue, so if I can't find one for that price, I may go with a cheaper one, like this Velleman. If it can read as accurately as the Fluke, that may be my best bet. I don't foresee using this too often. Just want to build two, maybe three amps from Bottlehead.

[Grainger49]

I won't use up Doc's space with posts on auctions that will be useless in a week.  PM me and I will send you some links of promising meters.

After a few minutes of searching I see a Fluke 77 with probes and the rubber case with a buy it now of $49.  That is under $50.  If you are interested PM me.

[denti alligator]

How do I tst a multimeter once I have it to make sure it's working properly? Can I do that without any parts from Bottlehead?